Timothy Leary studied the effects of psycholocybin before and LSD later. His thesis is that with just dosages, in a protected environment, and with reference figures (the great priests mentioned in the book) the effects of the substance can be beneficial. This text tells the experience of sixteen psychedelic "journeys" before the LSD was declared illegal. The guide to these journeys is found some great priests, who in reality were the crucial characters of the "off" history and literature of the Sixties: William S. Burroughs, Allen Ginsberg, Aldous Huxley, Alan Watts, Peter Orlovsky, Ralph Metzner. Each chapter also includes reading a Ching sign on changing living forms and chronicling what happened during the different journeys.