Leo Zeff (1912 – 1988) was a pioneering psychedelic therapist and researcher focused on LSD, MDMA and other psychoactive drugs. He conducted much of his work and practice underground after psychedelics were declared illegal in the 1960s. By the time he turned 70, Zeff was single-handedly responsible for the introduction of psychedelic compounds in use globally among nearly 4,000 individual therapists/practitioners.

The Secret Chief Revealed is written as a transcription of an interview conducted in the 1980s with Zeff about his research, studies, and practice with psychedelicassisted therapy. The revised 2nd edition maintains much of the 2nd edition release, including thoughtful contributions on Zeff’s lifework/research from other leaders in the psychedelic movement including Albert Hofmann, discoverer of LSD, psychedelic researcher and author, Stanislav Grov, a founder of transpersonal psychology, and Ann & Alexander Shulgin, renowned psychedelic researchers and authors, who also mention Zeff in Pihkal: A Chemical Love Story.