The Psychedelic Experience: A Manual Based on The Tibetan Book of the Dead (commonly referred to as The Psychedelic Experience) is a book about using psychedelic drugs that was coauthored by Timothy Leary, Ralph Metzner and Richard Alpert, all of whom had previously taken part in research investigating the therapeutic potential of psychedelic drugs such as LSD, psilocybin and mescaline in addition to the ability of these substances to sometimes induce religious and mystical states of consciousness. Started as early as 1962 as part of the Zihuatanejo Project in Zihuatanejo, Mexico, the book was finally published in August 1964.