This volume was born from the desire to expand the debates and exchanges initiated in O Uso Ritual da Ayahuasca ("The Ritual Use of Ayahuasca"; Campinas: Mercado de Letras, 2002, 1st edition, 2004, 2nd edition), edited by Beatriz Labate and Wladimyr Sena Araújo with the collaboration of Sandra Goulart. This second book considers diverse substances including ayahuasca, Virola snuff, Mimosa, iboga, coca, tobacco, Cannabis, and others. Still, this volume does not cover all ritually used psychoactive substances across the globe. Notable lacunae include the mescaline-containing cactus species peyote (Lophopora williamsii), widely used by indigenous people in Mexico and by the Native American Church in the United States, and San Pedro (Trichocereus pachanoi), from the shamanic complex of northern Peru. The ritual use of psilocybin-containing mushrooms (Psilocybe, Stropharia, Conocybe, Panaeolus) by indigenous groups of Mesoamerica is also not covered. The book takes into account the diversity of ritual plant-based psychoactives used especially in Brazil and South America, as well as one example from Africa.

All chapters represent never-before-published work, mostly by anthropologists, but also including works by a historian, a medical doctor, and an ethnobotanist. All of the researchers whose work is included have maintained long-term connections with their study sites and subjects. In some cases, authors revisit their own prior research from a new angle. Such is the case for Robin Wright. Although he has written previously about the use of Virola snuff among the Baniwa of the Upper Rio Negro, this is the first time he explores the symbolic meaning of Virola consumption, reflecting on it as the basis of a historical praxis. Echeverri and Pereira use their own personal experiences to understand the social and bodily disciplines enacted by indigenous Amazonian users of coca and tobacco. Samorini likewise pays special attention to Bwiti initiation rites which seek to produce a kind of induced coma, and which he himself also experienced. Grünewald, who has studied the Atikum for over a decade, reveals his own involvement in the production, consumption and expansion of the "vinho da jurema" (Mimosa "wine" or brew) in urban Rio de Janeiro.

Based on the discussions that emerged from the first volume, we realized that ayahuasca, used in various cultural contexts, was not an isolated or exceptional case. Rather, ayahuasca use can be compared to a series of other phenomena in which the consumption of psychoactive substances is central to the elaboration of intricate symbolic and ritual complexes. The term "psychoactive" covers a broad category of plants and chemical substances that act on the mind. At the beginning of the 20th century, the pharmacologist Louis Lewin classified them into five main groups: excitantia, hypnotica, phantastica, euphorica, and inebrianti. In the 1950s, a group of researchers led by J. Delay proposed a classification including only three main groups: psychoanaleptics, which are the stimulants, psycholeptics, the sedatives, and psychodisleptics, the hallucinogens (Seibel and Toscano 2001).

The use of such substances in religious contexts is common and extensive, arising in different cultures and historical moments. All of the articles in the book present examples where altered or amplified states of perception, induced by psychoactive plants, structure cultural, religious, ritual, religious or mythic systems. Such is the case for Mimosa (jurema) used among Indians of northeast Brazil, coca leaf as chewed among native peoples of the Colombian rainforest, various snuff species used by Amazonian indigenous societies, and the powerful iboga brew made from the root and bark of an African shrub.

Gordon Wasson and colleagues coined the term "entheogen" to designate psychoactive substances that enable contact with or reveal the spiritual world or divine entities (Ruck, Bigwood, Staples, Ott & Wasson 1979). The word is derived from the Greek entheos, "inspired, possessed by a god", plus geno, "to generate, produce" (Liddell & Scott 1997). Thus, a literal translation of "entheogen", and its adjectival form "entheogenic", would be "that which produces divine inspiration or possession". Edward MacRae (1992:16) translates it as "that which leads the individual to have the divine within". Some authors, including several in this volume, use the term "entheogen" in opposition to the commonly used term "hallucinogen", which is derived from the concept of "hallucination" and thus implies that these substances produce a false or illusory perception of reality often associated with psychopathological states. There are several sources for the origins of the term "hallucination". Some suggest it is derived from the Greek al'uein or hal'uein meaning "disordered thinking", "to be distraught", "to be absent, perplexed", or "to be outside oneself" with exultation or happiness (Ernout & Meillet 1967). Thus it might be possible to establish a connection between "hallucination" and "ecstasy", from the Greek ek ("outside") plus statis ("to be situated, positioned"; Liddell & Scott 1997); "to be out of one self", either by sadness, perplexity or happiness. A more direct etymological connection, mentioned in Webster's English Dictionary and the Petit Robert for French, is found with the Latin hallucinari, "to wander in the mind, ramble in thought". Only in the 15th century did the term acquire a pejorative meaning in the sense of "to be mistaken, deluded" (Narby 1997:180). The term "entheogen", by contrast, emphasizes the authentic character of these experiences and their importance in constituting ritual, mythic, and religious realities. In this sense we follow the arguments of Mircea Eliade (1986: 7), who claims that myths should not be understood as fables or fictions, but rather as truths held sacred and exemplary in certain societies.

Thus, some authors, including several in this collection, choose to use the term "entheogen" instead of the more established term "hallucinogen" in order to avoid its implications of false or deluded thinking. Moreover, the term "hallucinogen" emphasizes the perceptual aspects of altered states of consciousness and understates emotional and intellectual elements that are also characteristic of these states. Not all authors use the term, however. Narby (1997: 180), for example, chooses not to use this neologism, since it represents a further extension of an already complicated debate over a concept that is difficult to define and understand. Another frequently used term for plants and substances that produce altered states of consciousness is "psychedelic". The term, coined by the psychiatrist Humphry Osmond in the 1950s and later adopted by the counter-culture movement in the 1960s and 70s, is composed of the Greek psyche, "soul" or "spirit" and delic, "that which is visible, clear or manifest". Thus the term was coined to mean, "that which manifests the spirit or soul" (Houaiss 2001). However the Greek derivation is flawed, since according to orthographic norms it should be rendered "psychodelic", as is the case for other terms coined from the same root ( "psychology", "psychoactive", etc.). This leads to a degree of orthographic irregularity in English usage. As incorporated into Portuguese and Spanish, "psicodélico" maintains proper orthography. However, most English-language authors prefer to use the original, if orthographically flawed, term "psychedelic" to avoid any implication of relationship between "psychodelic" substances and "psychosis". In contrast to "entheogen", with its emphasis on religious and mystical experience, the term "psychedelic" is associated more with recreational use of these substances. Yet, as noted by Henrique Carneiro in this volume, profane connotations for "psychedelic" were adopted more in the 1960s through the popularization of the counter-culture movement. Initially, "psychedelic" included sacred contexts of substance use. Thus Ott (1993: 103-105; see also Ott 1995, pp. 128-129) defines psychedelic as "an entheogen, sacramental plant or shamanic inebriant that evokes religious ecstasy". Yet the term bears clear modern associations with the "psychedelic era" and recreational, non-traditional use of substances like LSD. This indelible association with the political, artistic, and pop music movements of the 1960s renders the term inappropriate to refer, say, to a traditional shaman using "psychedelic" plants or substances.

Another term that came into use, beginning in the 1960s, is "plants of power", also associated with the counter-culture movement and associated especially with the writings of Carlos Castañeda (1968, 1971). In The Teachings of Don Juan and subsequent best-selling books, Castañeda writes about his experiences of initiation with the pseudonymous (and perhaps fictional) master Yaqui shaman Don Juan. The initiation process ascribes a central role to psychoactive plants like the mescaline-containing peyote cactus (Lophophora williamsii), Psilocybe mushrooms, and Datura stramonium in obtaining sacred knowledge and power. Throughout Castañeda's books, Don Juan repeatedly affirms that these plants function as vehicles that allow people to contact forces or powers that eventually permit the apprentice to become a "man of knowledge". A point frequently made in the teachings of Don Juan, as told by Castañeda, is that the altered states of perception and consciousness produced by these plants should not be understood as hallucinations but rather as reality, albeit a different and not immediately perceptible reality.

We will not enter here into the ample and controversial debates over Castañeda's work and the veracity of his accounts (see De Mille 1980). Bruce Lamb's account of the trajectory of Peruvian ayahuasca shaman Manoel Córdova-Rios in Wizard of the Upper Amazon has also been questioned and criticized. For a defense of the positive role of "imagination" in creating this narrative, see Luna & White (2000: 8).

For the purpose of introducing this volume, what we take from Castañeda's work is its emphasis on a worldview that considers the consumption of psychoactive substances to be not only positive, but also central to acquiring certain kinds of knowledge about reality. For this reason they are considered "plants of power", amplifying and deepening ordinary human vision and perception. It is in this sense that we chose the title of the present volume.

Although the term "plants of power" emerged within the counter-cultural movement and later become popularized among certain groups who are strongly influenced by the cosmopolitan "New Age" culture, we chose the term precisely because it seemed to be closer to the concepts of traditional societies about the properties and characteristics of these plants. "Plants of power" is close to the concept of kepigari among the Machiguenga Indians of Peru, studied by Shepard in this volume. Kepigari translates literally as "toxic" or "poisonous", however such toxic properties do not always have a negative connotation, since through some kinds of intoxication, a cure can be obtained. Indeed, for the Machiguenga, physiological toxicity, mental effects, and spiritual transcendence cannot be separated, as these various effects are linked to the euphoria and ecstasy of the journey to the ancestral world, where central cosmological relations are ordered. These plants, often conceived of as being inhabited by a spirit or "mother", are intelligent beings with their own personalities and will, with whom humans can build educational and profitable relationships. The Machiguenga describe these beings, and the plants they inhabit, as "fearful" or "awe-inspiring". In this respect, these concepts are similar to the term proposed by Luis Eduardo Luna (1986), "master plants", which is to say, "plant teachers", associated specifically with the vegetalismo tradition of mestizo ayahuasca use in Peru. In another sense, the term "plants of power" is related to popular imagination and notions around more contemporary contexts of use of these substances; for example, the Brazilian ayahuasca religions that reinterpreted various concepts of the Peruvian vegetalismo tradition studied by Luna (Goulart 1996).

But what exactly do we mean when we speak of "ritual use of plants of power"? The initial idea was to separate ritual from non-ritual use of psychoactives, which is to say, to exclude illicit, non-sanctified or non-traditional contexts commonly referred to as "drug use". However, a question immediately presented itself: What is ritual? The concept, which is important both politically and from the native point of view, has a long history in anthropology and its definition is far from consensual. Although it is not possible to delve fully into these debates here, we shall mention a few considerations (see Labate 2004). Most anthropological theories see ritual as a symbolic act that marks a distinction in relation to daily activities, whether in terms of form or function. Durkheim (1989 [1912]) emphasized ritual as a passage from disorder to order, a domestication of chaos through strengthening the ties of the individual to the society. In this line of interpretation, followed by many anthropologists, ritual is, above all, a means of affirming the unity and integrity of social structures, even if it involves representations of conflict over social norms (Gluckman 1963). Turner (1974a, 1974b) borrowed Van Gennep's (1978) notion of rites of passage consisting of three phases--separation, liminality and reaggregation--to theorize ritual as a process capable of including, in its liminal phase, a rejection of social order. Studying various historical and contemporary cases from Europe (medieval religious orders, Thomas Beckett), Mexico (Hidaldo), Spain (the Santiago pilgrimage), the United States (the hippy movement, contemporary art), Africa (mainly the Ndembu of Zambia), India, and China, Turner's work inspired an approach to ritual centered on theatricality, performance and the experience of participants. Indeed, in his later work, Turner (1982, 1985) turned toward reflections on theatrical experience.

In Brazilian anthropology, Da Matta (1990) followed the insights of Van Gennep and Turner's early work in his analysis of carnival parades and processions as dramatizations of the dilemmas of Brazilian society. More recently, some have explored the idea of ritual as a model for the analysis of different kinds of contemporary social events, seen as a part of political processes (Peirano 2001). In terms of definitions of ritual, we see a combination of different emphases even within the work of a single author. Even in Durkheim's classic texts--generally associated with the functionalist school where ritual is seen as reinforcing social structure--one perceives a concern for and analysis of other dimensions that might be labeled in contemporary parlance as ritual performance of the participants. In his seminal work Elementary Forms of Religious Life, Durkheim (1989[1912]) describes numerous rites and minutely analyzes diverse ritual attitudes through which different cultures manifest and experience values and symbols. In this sense, ritual can be understood as a manifestation of social relations and reinforcement of social structure, but at the same time as a product of individual expressions of symbolic identity. Moreover, we find in Durkheim an overall concern with the efficacy of rituals in reinforcing collective sentiment and representations.

A more contemporary anthropologist like Geertz (1978), although he is best known for his critical revision of classic anthropological approaches to culture, likewise emphasizes the importance of ritual behavior in affirming social representations, though his perspective is quite different from Durkheim's. For Geertz (1978: 149), religious rituals provide "an appearance of objectivity" with respect to certain cultural values and worldviews. For Geertz, more than a symbolic expression of the natural order of society--as is the case for Durkheim--ritual is understood as a text that transmits cultural messages, discourses and interpretations about a certain culture; these are ultimately analogous to the anthropologist's own interpretation of these cultural phenomena. Thus ritual has been approached in diverse contexts and forms throughout the history of anthropology.

Authors like Jeremy Narby (1997) and Jean Langdon (1996) have likewise demonstrated how the concept of shamanism, like that of ritual, has changed through time, reflecting the history of the anthropological discipline and its paradigms. Thus Taussig (1993), in his critical evaluation of the yagé ritual among indigenous peoples of the Colombian Amazon, rejects the Durkheimian explanation of ritual. For Taussig, an emphasis on the ritual as a structuring process, and the shaman as an agent of order, misses the true nature of the yagé ritual, which is characterized more by disconnection, improvisation, collage, heterogeneity, mixing, rupture, poetic language: an allegorical, rather than a symbolic mode. Taussig sees the yagé ritual as an "illusionist theater". In other passages, he refers to it as "epic theater" and even compares it to the work of Artaud. Taussig, associated with post-modernism in anthropology, exemplifies many of the central themes of this analytical movement in his approach toward ritual.

We do not aim to dismiss these various approaches or reduce them to mere reflections of predominant theories. Because the various chapters are based on different perspectives and theories without an exact consensus as to the definition of the term, it is probably useful at this point to provide an extensive definition of "ritual". Despite variations, the diverse chapters in the volume emphasize how the rituals in question always affirm or exemplify important elements about the structure of a particular society, culture or group, whether in the sense of reinforcing certain aspects, norms, values, etc. (i.e., in the classic Durkheimian formulation), or to point out processes of conflict and change (as Gluckman and Turner would have it), or as expressive commentary on social life (as in Geertz), or even perhaps as a chaotic, poetic mode (as in Taussig's perspective).

In reading the various articles presented here, it becomes apparent that rituals create special spaces and moments that can be distinguished from and contrasted with ordinary daily life. The contrast with daily reality always appears to establish itself by means of certain operations, mechanisms, rules, principles and, above all, by means of a specific kind of language and logic that we could refer to as symbolic. In the special, extraordinary universe constructed by ritual, specific actors, actions, representations and social relations are emphasized, always responding to a collective sphere, even if the subjective experience and individual ritual performances are also important. Thus the volume includes chapters that reflect, for example; on ethnic identity among indigenous groups of northeast Brazil; conflicts among different groups within the same religious movement, as well as different alignments among their followers; important elements of initiation and apprenticeship in certain groups or cultures, and the ambiguities within social structures.

Such rituals are symbolic and create realities; which is to say, they have the capacity to interfere in the real world. A common theme found throughout all of the works is how the extraordinary reality highlighted and revealed in the various rituals under study are all defined, namely, by the consumption of plants of power. In this sense, we can affirm that the use of psychoactive substances in ritual contexts allows societies and groups to reflect on their dilemmas and orient their actions towards addressing and resolving these conflicts. At the same time, we see how the ritual use of plants of power proves to be extremely efficient in fusing the reality, perceived and experienced subjectively, with the collective conceptions and representations built around this reality. To say it in a different way, plants of power consumed ritually allow the fusion of practice and belief, attitude and thought, subjectivity and collectivity. This, perhaps, is where the true power of these substances resides.

Even though the majority of contributions to this volume discuss the use of psychoactive substances in religious rites and ceremonies, this does not mean that the authors define ritual as an exclusively mystical or magical space, moment, or universe. On the contrary, several chapters present perspectives that break with reductionist dualisms between sacred vs. profane, magic vs. science, irrational vs. rational, and so on. More than just conceiving of an essential difference in ritual action, these contributions point toward the complexity and variety of implications of these practices across different spheres of human and social life.

The sphere of the "sacred" appears, in several chapters, as an extremely broad realm. Thus, in Shepard's contribution, the Matsigenka shamanic system is conceived as a dynamic complex of concepts that crosscut multiple spheres from myth, to botany, to medicine, and so forth. Likewise, Echeverri & Pereira show how coca (ipadu) consumption among indigenous Amazonian populations is simultaneously ritual, politics, and religion. Grünewald relates the discussion of ritual use of jurema (Mimosa) to themes that range from indigenous shamanism, to ethnic identity, to political conflict and processes of cultural globalization (cf. Ortiz 1994). Even in Wright's chapter on Baniwa use of Virola and Banisteriopsis, focus on classic anthropological themes of mythology and shamanism and religion and myth are presented as dimensions of social life that have an extensive power of action. Wright shows how Baniwa prophets and shamans have guided and influenced the political stance of this society.

The representation of the sacred is central to most of the rituals, rites, and religions studied in this volume. Neither treating the sphere of the sacred as isolated, opposed to, or independent from other domains of social life, nor reducing the sacred to a simple representation of these other domains, the various contributions in this volume express a vision in which the religious realm is in constant communication and exchange with other spheres (economy, politics, culture, etc.) of social life. The religious phenomena discussed in the diverse chapters of this volume are presented in a way that makes explicit the close and complex relationship between worldview, symbols, practice, rites, subjective experience and institutions. These different aspects are considered by various authors from diverse perspectives revealing a conception of religion in which symbolic and moral systems are analyzed without losing sight of their relationship with social structures.

One of the central objectives of this volume is to emphasize and reassert the relevance of the theme of psychoactive substances and altered states of consciousness, especially in the social sciences. It must be remembered, however, that the study of psychoactives is not new, but rather has had a significant role in the history of modern Western science. Thus, 19th century discoveries of, and experimentation with, psychoactive drugs helped contribute to the foundation of the discipline of psychology, providing instruments for producing different states of consciousness and permitting the observation of the "I" or "oneself" as never before. In this way, curious souls have been seduced, time and time again, into using psychoactive substances as a tool for self-reflection and knowledge. An experimental attitude towards consciousness inaugurates a kind of science whose object is the very observing subject. The instruments that produce altered states of perception allow a broadening of the range and distinctions between the three basic kinds of consciousness: waking, dreaming, and dreamless sleep. Opium and hashish bring the dreams of sleep to the waking state, compounding the two into a new kind of state. Anesthetics bring dreamless sleep to the waking state, chemically suppressing wakefulness so thoroughly that it becomes possible to carry out painless surgical interventions. Drugs were seen through the Romantic imaginary in the early 19th century as a tool for dreaming. It is worth mentioning Thomas de Quincey's (1995 [1821]) pioneering autobiography that inaugurated a new literary style describing drug experiences and inspired numerous later 19th and 20th century writers including Edgar Allan Poe, Baudelaire, and others.

The theme of dreams was already part of the poetic repertoire of Romanticism, but drugs brought new experimental data to traditional notions about the "fantastic". The precise nature of sensations, perceptions, thoughts, and emotions produced by drugs became more than an amplified set of literary images and themes; they became a privileged means towards the scientific study of the mind. Throughout the 19th century, psychoactive substances, both traditional and synthetic, were an object of study and reflection in the nascent psychological and human sciences. William James (1929), one of the founders of modern psychology, called attention to the role of drugs in producing mental states analogous to mystical and religious trance. Influenced by his own experiences with nitrous oxide, he identified certain features that could be considered characteristics of "mystical states of consciousness". Sigmund Freud (1978 [1930]), an avid cocaine user and proponent for several years, was one of the first to theorize on the role of psychoactive drugs in the chemical pathways of libido, identifying these drugs as the most efficient mechanism for inducing pleasure and reducing pain. From the very early stages of his elaboration of the theory of libido, Freud tried to integrate it with the tenets of the natural science of his time, considering the libido as a kind of energy, subject to the laws of thermodynamics and possessing of a biochemical substrate. Freud's ambition was to elucidate the thermodynamics of pleasure, a kind of mathematics of joy, which would include both sexual pleasure and the euphoria produced by drugs. He expressed this idea clearly in a 1908 letter to Karl Abraham in which he affirms, "the Soma potion seems to contain the important presentiment that all our intoxicating liquors and stimulating alkaloids are merely a substitute for the unique, still looked for toxin of the libido that rouses the ecstasy of love" (Santiago 2001: 90, our translation) Sociologists like Durkheim and philosophers like Nietzsche also emphasized the role of psychoactive drugs as vehicles for producing ecstasy and as social lubricants.

This volume contributes to this discussion, seeking to enrich human science approaches to psychoactive plants through studies that reveal specific aspects of the cultural contexts of their traditional use in Brazil and other regions of the world, while also highlighting the most important contemporary debates and reflections about these substances.

The opening chapter by Henrique Carneiro serves as a historical introduction to the theme of psychoactive drugs. He reviews the past 150 years of studies on psychoactive substances, which he considers represents a new field of epistemology. He also considers the history of drug regulation. Carneiro covers different aspects in the history of psychoactive use: traditional sacred uses, the psychedelic movement of the 1960s and its resurgence in the 1980s, military and political uses of hallucinogens as well as psychotherapeutic uses. The chapter carries out a critical evaluation of prohibitionist policies towards drugs, which have intensified since the 1960s (see also www.neip.info).

Questions emerging from the study of shamanism, myth, and cosmology in traditional societies appear in many of the included chapters, but a few deal with the relationship between these themes and psychoactive substances in particular detail. Robin Wright's contribution, the second in the volume, considers the use of Virola snuff and the Banisteriopsis vine brew among the Arawak-speaking Baniwa of the northwest Amazon. Both substances are considered sacred by Baniwa shamans and prophets and are central to their practice. Virola is usually used in conjunction with Banisteriopsis and fulfills a central function in shamanic healing. Continued use of Virola and Banisteriopsis also allows shamans to transmit messages and revelations that assist the Baniwa through the crises and dilemmas they face. Wright's article also points the way towards a new understanding of historical and religious movements among indigenous peoples of the northwest Amazon, highlighting the role of psychoactive plant use in renovating and updating mythical and ethnohistorical narratives.

Wright's observations and analysis allow us to visualize the close relationship between psychoactive substance and shamanic practice. The chapter points to a series of factors that support the idea that consciousness-altering plants are often used by indigenous populations in South America within the context of shamanic initiation and apprenticeship. This idea was first presented explicitly by Métraux's (1944) comparative ethnological works, an analysis that contrasts with Mircea Eliade's (1986) historical and essentialist approach that envisions a "pure shamanism" devoid of such practices. For Eliade, the use of psychoactive plants in initiation and spiritual development represents a kind of degeneration from the original, pure and true forms of shamanism. For Métraux, by contrast, the use of these substances is construed as a constant and central element of shamanic practice for many South American shamans. At the same time, the use of these plants is closely tied to the techniques and therapeutic role of the shaman or pajé, a Brazilian term used by several other authors (from the Tupi piai, referring to such magical-religious agents [Métraux 1944]).

A few observations are in order: First, to say that psychoactive substances are present and important in some shamanic contexts does not mean that all shamanic practices depend upon or are universally associated with these substances. There are, for example, forms of shamanism that depend on other techniques such as songs, prayers, drums, dreams, etc. Furthermore, it is important to point out that "psychoactives" include a variety of substances (from ayahuasca to tobacco to alcohol) with vastly different properties and effects. According to different specific contexts, as mentioned in several other contributions, one or more substances may be consumed according to various hierarchical relationships among them, depending on different intentions and uses: healing, hunting, warfare, cosmic ordering, etc. Finally, it is worth remembering that there are techniques of altering consciousness, not necessarily related to shamanism, that do not involve any psychoactive consumption: auditory stimulus, diets and fasting, social isolation, sensory deprivation, meditation, sleep and dream states, sexual abstinence, extensive motor activities, endogenous opiates and mental states that result from neurophysiological or chemical alterations such as epileptic seizures (Winkelman 1992; Barbosa 2001).

The extensive social role of psychoactive plant use is also highlighted in Glenn Shepard's chapter about the Matsigenka, an indigenous group also of Arawakan affiliation inhabiting the montane rainforests along the eastern slope of the Andes in Peru. The Matsigenka consume a wide range of psychoactive plants, including tobacco, Brugmansia and other Solanaceae species, and ayahuasca, among others. The diverse plants are in turn associated with a wide range of uses from mundane to sacred, and from magical to medical to shamanistic. The Matsigenka present an impressive example of a society that organizes and structures various spheres, dynamics, and tensions around the use of specific and varied psychoactive plants. In the religious sphere, specifically shamanism, psychoactive plants play a central role for the Matsigenka. Among the various plants used, tobacco plays a central role and is directly associated with the powers and techniques of the shaman. The author observes that tobacco paste, for example, is construed as a magical substance that is central to the shaman's powers and abilities. Thus, tobacco can be used as a weapon, like a magic dart to attack enemies, or as a kind of magnet to suck out pathogenic objects lodged in a patient's body. Matsigenka tobacco use is linked to one of the most well known and widely commented shamanic practices in the Americas, namely the extraction of hidden pathogenic objects believed to underlie the etiology of many illnesses (Lévi-Strauss 1989: 202-213).

While Matsigenka shamanism represents a religious system, it also includes a set of practices and beliefs that affect and influence other spheres of social life. In this sense, Shepard's contribution is allied with contemporary conceptions that understand shamanism as a total cultural or cosmological system (Chaumeil 2000; Langdon 1996).

In their chapter, Juan Alvaro Echeverri and Edmundo Pereira examine the use of ipadu, a powdered preparation of coca leaf (Erythroxylum coca), in the Vaupés and Caquetá-Putumayo region of the Colombian Amazon. Here the work departs from traditional studies of coca that focus on the Andean region. The study, which represents collaboration between a Colombian and a Brazilian anthropologist, presents a whole suite of innovative ethnographic data on coca use in this region, as well as a theory as to how it was introduced to Amazonia. They take a detailed look at various myths concerning coca collected mostly from the Huitoto and Muinames of the Caquetá-Putumayo. As in the chapters mentioned earlier, their description reinforces the idea that coca use in Amazonia involves multiple, interpenetrating spheres of social life. To chew or "mambear" coca is part of a whole "culture of mambeo" that is implicated in masculine initiation, embodied education, and interethnic mediation as well as in political, moral and religious acts. The chapter refers to a series of bodily practices and precautions surrounding coca use, and affirms that the culture of mambeo includes a rigid bodily discipline that is integrally linked to a "discipline of the spirit" as well.

The three chapters dedicated to the psychoactive beverage jurema (Mimosa spp.) highlight the great versatility of uses of this substance. Indeed, the tremendous diversity of uses implies more than just a distinction among different rites, modes of preparation, and plant admixtures: It seems that these practices may involve distinct botanical varieties of the same species. The term jurema refers to an enormous diversity of substances, modes of consumption, and meanings. Each article, in turn, focuses on different themes and concerns. Clarice Mota discusses the use of jurema in different cultural contexts, with special attention to the indigenous groups of northeast Brazil. In her analysis, the cult of jurema has gained relevance in relation to the process of identity construction and indigenous self-consciousness. In his chapter, Roberto Motta seeks to understand the reappropriations of indigenous uses of this plant in Afro-Brazilian religious rites. He traces the history of jurema or "catimbó-jurema", highlighting its stages of development and reflecting on its role in the domain of what he refers to as "Afro-Indo-Brazilian" religions. Grünewald undertakes an original interpretation encompassing indigenous consumption of jurema as well as contemporary usage in middle class urban settings, including the expansion of jurema to other countries. According to Grünewald, jurema has a central role in constructing indigenous identities through a complex process of contrasts that reveal the political strategies of diverse groups. However, questions of identity are not restricted to traditional contexts. The chapter makes an important and novel contribution by revealing how identity construction in contemporary society can also be related to psychoactive plant use, evoking complex issues, such as a transnational network of communications through which information and symbols circulate.

Another important set of themes that recur throughout the volume is the relationship between "traditional" and "modern" modes of consumption of psychoactive substances. According to several authors, European colonization and Christian appropriation of pagan traditions led to the development of so-called "mixed"-- ethnically diverse as well "syncretic"--contexts of use of those same ancient psychoactive plants that had so disturbed the chronicle writers and missionaries. Examples include the Brazilian ayahuasca religions, Bwiti in Africa, and the Native American Church. Debates around syncretism are a classic theme in the literature on cultural contact covering various cultural phenomena, especially religion. The concept of syncretism has already been criticized within the anthropological literature, since it implies a kind of collage made up of supposedly "pure" elements: an improper and disarticulated juxtaposition. This concept has been criticized by noting that this supposedly pure prior or original state never existed. Elements of diverse origins do not need to be articulated in an architecturally cohesive and closed system.

The chapters by Antonio Bianchi and Giorgio Samorini are a good illustration of these debates. The authors attempt to understand the historical formation of Peruvian vegetalismo and the Bwiti cult in Africa, showing how the consumption of ayahuasca and iboga, respectively, acquired new meanings and features in these contemporary contexts, all the while appropriating the legacy of traditional native practices. Bianchi's provocative contribution problematizes those approaches that suggest a supposedly linear evolution from indigenous ayahuasca shamanism to the mestizo vegetalismo tradition practiced among riverine populations in Peru. Following Gow's (1994) analysis, Bianchi affirms, contrary to many scholars who have confused native explanations with history, that mestizo shamanism developed far from indigenous contexts, which is to say, that it is especially tied to cities and the context of modernization. In strictly indigenous shamanism, ayahuasca is not central, nor does it operate mostly as a therapeutic agent, as is the case with vegetalismo. It is the vegetalistas, rather, who later exported this model of ayahuasca-based healing back to diverse indigenous groups. As an example of this process, Bianchi cites the Matsigenka, studied in detail in the chapter by Shepard. Indeed Shepard's contribution provides complementary information to Bianchi's argument, noting that the use of Psychotria leaves as a potentiating admixture to ayahuasca was introduced very recently among the Matsigenka of Manu Park as a result of their contact with missionary groups in the second half of the 20th century. Luna (this volume) defines "classic ayahuasca" as the brew prepared from the liana Banisteriopsis caapi (Malphighaceae) and leaves of Diplopterys cabrerana (also Malphighaceae) or Psychotria viridis (Rubiaceae). However, other kinds of ayahuasca may include other additives: the term "ayahuasca" must always be questioned and problematized.

On the other side of the Atlantic, in equatorial Africa, we learn about a religious context rarely mentioned in the Brazilian anthropological literature: the cult of Bwiti, which focuses on the consumption of the root of iboga, a psychoactive shrub. Giorgio Samorini outlines the historical formation of what he denominates "syncretic Bwiti", the product of re-elaborations based on pygmy traditions and French Christian missionary activity beginning in the First World War. This diversity is reflected in the rich mythology of Bwiti, described by this author. Bwiti is notable in the way it integrated, within the context of modernization, an ethnic population, the Fang, and members of the political and military hierarchies of Gabon. According to Samorini, Bwiti probably represents the largest entheogenic religion in the world.

This and other chapters, including those concerning the Brazilian ayahuasca religions and the diverse modalities of jurema use, reveal the difficulties of marking precise dividing lines between the "traditional" and the "modern", the "ancient" and the "contemporary". Echeverri and Pereira also examine this problem in their chapter on coca in the Amazon that, contrary to what the indigenous mythical narratives claim, was probably introduced to the region in the late 18th or early 19th century.

The dichotomies between "traditional" and "modern" uses, "indigenous" and "western" uses, "sacred" and "profane" contexts, and even "natural" vs. "synthetic", or "mild" versus "hard" drugs harbor a certain prohibitionist discourse which asserts a naturalness and moral supremacy of the former over the latter. We consider it problematic and unjust to recognize or grant the rights to use certain substances by so-called "traditional populations" by virtue of the fact that they have a historically proven tradition of consumption. This is the case, for example, of peyote in the United States, where possession and use of the peyote cactus is prohibited except for federally recognized tribal members. Note that there are some variations by state; for example a Texas law that restricts peyote consumption to those having at least 25% indigenous ancestry (The 1994 American Indian Religious Freedom Act and other documents pertaining to the religious use of drugs are available at erowid.org).

Various chapters in this book suggest, however, that rituals surrounding the use of psychoactive substances undergo a constant process of creation and reinvention. This is, of course, the old maxim of anthropology: Culture is dynamic; which is to say, it is in constant transformation, and this transformation implies the rupture of some of the dualisms noted above. These are not mere theoretical questions, of interest only to scholars and specialists. They are issues that have immediate consequences for the current laws relating to psychoactives in several countries. These laws protect certain groups' use of psychoactive substances while at the same time resulting in persecution and stigmatization when the same substances are used by other social groups, or in other contexts. Many authors have pointed out the association between the prohibition of psychoactive drugs and the repression of certain social groups. Bruno Cavalcanti's chapter in this book associates the legal prohibition of Cannabis sativa in Brazil with the repression of Afro-Brazilian populations (see also MacRae & Simões 2000: 19-27).

The collection highlights the importance and centrality of ritually used psychoactive substances in human cultural formations. As a whole, the various contributions reveal contrasts and differences, as well as regularities and common elements, across diverse contexts of the consumption of plants of power. Many of these features are quite compelling and indicate the necessity of further comparative research. If Christianity has availed itself of pre-Christian pagan traditions, this process of religious appropriation is a two-way street, as seen in recurrent symbolic constructions such as: Bwiti members who claim to be "true Christians" or assert that the tree of knowledge was in fact iboga; certain Santo Daime branches who treat the daime (ayahuasca) beverage as the "blood of Christ"; and, likewise, the Indians of northeast Brazil who consider jurema to be the blood of Christ. Finally, as reported by some authors, and according to popular legend, the mescaline-containing San Pedro cactus of Peru was so named when the indigenous populations, after coming into contact with Christian ideas, affirmed that they already had the "key to the gates of Heaven".

Taking a different approach, Luna examines ayahuasca use in the upper Amazon through an analysis of different groups' practices, rites, and myths. He identifies common elements and themes that repeat themselves in diverse cultures. One of the most common themes in the ayahuasca experiences of indigenous Amazonian societies is the transformation of humans into animals, and, in a broader sense, the exploration of the natural world. Luna argues that ayahuasca use allows these populations to achieve greater knowledge about and respect for the environment in which they live, thus enriching their cultural understanding of nature. His reflections are based on the hypothesis that ayahuasca permits an expansion of human perception, constructing a kind of "pharmacopoeia of consciousness". Considering this, we could speculate that ritual ayahuasca consumption within traditional Amazonian societies is related to modern discoveries and debates, for example regarding the chemical functioning of the brain or the nervous system, as suggested by Narby (1997). Another major contribution of Luna's chapter is his detailed discussion of the botanical, pharmacological, and chemical characteristics of ayahuasca, inviting the reader to understand the complex mechanisms involved in the brew's efficacy. These aspects are not explored in the other chapters of the book, which focus more on symbolic dimensions of ritual and plant consumption.

Sandra Goulart's chapter opens the next section of the book, and focuses on the ayahuasca religions of Brazil: Santo Daime, Barquinha and União do Vegetal. She starts with an historical overview of these religious movements and discusses their processes of formation. She shows how all three involve reappropriation of indigenous practices and mixing them with diverse influences including Catholicism, Afro-Brazilian religions, Kardecist spiritism and the European esoteric traditions. From this basis, she concentrates on processes of distinction and continuity between these three religious traditions, focusing on the mutual suspicions and alliances that have occurred between them and thereby highlighting their apparent symbolic, ritual, and cosmological differences. By bringing to the fore these conflicts, she makes a significant contribution to the debate over religious phenomena, generally colored by a bias towards notions of equilibrium. Beyond this, Goulart's chapter brings new evidence to discussions of the process of religious identity construction. She shows that the process is complex and dynamic, and that the conflicts between opposing groups can be crucial to the definition of identity and boundaries. One of her assumptions is that representations about the Other also reveal projections of one's own identity.

The chapters following Goulart's continue the discussion of Brazilian ayahuasca religions, but analyze other problems related to the process of expansion and growth of these religions in recent years, as well as the legitimacy of ritual consumption in opposition to the prohibitive attitude towards illicit drugs in contemporary western society.

Beatriz Labate's chapter discusses the ethical, political, ecological, and social issues that emerge with the expansion of the ayahuasca religions throughout Brazil and the world. While the ritual use of psychoactive plants like ayahuasca creates little controversy among indigenous populations, the same can not be said when these plants go on to be consumed in religious or non-indigenous contexts. It is worth noting that the urban ayahuasca religions that emerged in Brazil beginning in the 1930s represent themselves today as "traditional" and now have a legitimate status recognized by the Brazilian state. Labate reviews the historical process of regulation of ayahuasca use and analyzes the legal and pharmacological discourses that permeate this debate. She shows how legality is not something clear and pre-defined, but rather a process of constant construction.

The chapter by Edward MacRae emphasizes the importance of the mechanisms of cultural normatization that have been developed by religious groups that use psychoactive substances. He analyzes the use of daime (ayahuasca) and "Santa Maria" (Cannabis sativa) within the CEFLURIS branch of Santo Daime, founded by Padrinho Sebastião Mota de Melo. While daime/ayahuasca use in Brazil has been legal since the mid-1980s for exclusively religious purposes, Cannabis use remains prohibited. In the case of Santo Daime, MacRae argues that socialization and favorable cultural conditions give rise to a series of effective group social controls. Prohibition, on the contrary, does not allow an institutionalization of ritual norms and uses, and thus hampers the development of effective social controls by users and increases the chances of possible undesirable effects caused by substance consumption.

Bruno Cavalcanti also takes up the idea that prohibition can function as a principal cause of undesirable effects in the case of Cannabis use. After a brief introduction to Cannabis in ancient times, he presents in detail the sacred and ritual uses of this plant in Brazil, especially among Afro-Brazilian, indigenous, and mixed-blooded ("caboclo") populations of the northeast. He suggests that the prohibitionist campaign launched throughout the 20th century probably interrupted a process of symbolic systematization and ritual construction of these diverse uses, pushing them towards profane and marginalized settings.

Various chapters, each in its own way, focus on the problems of prohibition and legality of psychoactive consumption in the modern world. The ritual use of plants that alter perception leads us to new and diverse reflections on the use of "drugs" in contemporary society, far beyond the conventional debates and positions on this question. Generally, and especially in the chapters by Labate, MacRae, and Cavalcanti, various authors present evidence that, in addition to police, legal, and even medical controls, there are various other kinds of social controls exerted on the consumption of psychoactive preparations in diverse societies and historical periods. Such controls are supported locally, and are generally more efficient than external, coercive and universalizing regulations. We note how medical controls become institutionalized when the state uses medical opinions to justify policies in the area of public health. Such opinions, however relative or partial, are presented to the society as consensual, natural, and universal. Some examples of these processes can be seen in recent court cases in the United States concerning addiction, where a kind of "therapeutic justice", based on medical diagnosis, imposes norms of moral conduct on illicit drug users, who are then removed from a criminal category and placed in a disease category, and who must necessarily submit themselves to medical treatment and control. By contrast, local controls over psychoactive use--which sometimes preclude legal norms or codes--can be advantageous in different settings and occasions. These controls do not imply disorder, but rather represent local and cultural rules that institute other regulatory practices based on the choices of individuals and particular groups, not universal criteria. Rodrigues (2003), Zinberg (1984), and Grund (1993) also address this theme, reflecting on modes of consumption of illicit psychoactive substances and analyzing the existence of informal social controls that regulate their use. Indeed, MacRae's chapter on Cannabis use in this volume, which draws on the concepts of Zinberg and Grund, offers an example of how rituals can organize the consumption of a psychoactive substance in a specific context.

The nature of the diverse cultural experiences involved in the use of psychoactive substances has been studied by different scientific disciplines. Psychopharmacology and neurophysiology seek to identify biochemical processes in the brain. Anthropology, by contrast, privileges the cultural, ritual, symbolic, and mystical contexts of consumption. Ethnobotany assimilates scientific and traditional knowledge about these plants, while sociology studies diverse contemporary forms of use in urban and rural contexts. Psychology attempts to explain and interpret the use of psychoactive drugs in relationship to the construction of subjects and subjectivity. All of these disciplines, from their specific perspectives, provide tools to build a broader and more integrated field of knowledge that could be situated along the interdisciplinary boundaries of a general theory of drugs that has yet to be attained.

The phenomenon of consciousness is perhaps the central focus of philosophical, religious, artistic, and scientific reflection on the effects of psychoactive substances. So-called "altered states of consciousness", chemically produced, are an important paradigm for some of the most intense experiences of human cultures. They can be the focus of ecstatic devotion, aesthetic fascination, and spiritual inquiry. The chapters in this book represent multiple lines of investigation, predominately within the domain of anthropology, engaging in an intense dialog with other disciplines as they seek to plumb the multiple meanings of the use of "plants of power".