Ever since the "consciousness revolution" in the 1960s, dedicated spiritual seekers and scientific researchers from all continents have explored the world of psychoactive and hallucinogenic plants. In Ayahuasca, objective scientific information and the narratives of ayahuasca users -- shamans and others -- are presented together. Readers will also learn the pharmacology of this Amazonian plant. Ayahuasca is a tea made from two plants found, until recently, only in the Amazon basin. Indigenous people of the region have used it for medicinal and shamanic purposes since time immemorial. In the last century, it has been ceremonially incorporated by polyglot Christian/goddess religions springing up in Brazil and by seekers on the margins of consciousness exploration. In this book, Metzner, a hallucinogenic and mystical experience researcher for over 35 years, has compiled essays and journal-type writings from a wide assortment of people who have experienced its divinity-evoking effects--28 scientists, psychologists, chemists, curious laypeople, and practitioners of these religions. While uneven in literary ability, each contributor provides an insightful peek behind the curtain of an experience that until now has been shrouded in tribal secrecy and cult ritual--truly an adventure into the Amazon of the mind. In this book, we will provide a look at the phenomenon of ayahuasca both from the perspectives of objective natural and social science (botany, chemistry, pharmacollogy, medicine, anthropology, and psychology) and from the point of view of sujective experience - a realm usually not considered amenable to scientific investigation. To do so requires a new look at the epistemology of consciousness. Originally published in 1999 by Thunder's Mouth Press under the title Ayahuasca: Human Consciousness and the Spirit of Nature - second edition 2006 "Sacred vine of spirits: ayahuasca" - third edition 2014 : The Ayahuasca Experience - A Source Book on the Saacred Vine of Spirits. see 2006 second edition for full development.