In this work, Clark is a defender of, and cheerleader for, Timothy Leary, working from the "establishment" side. This is a rather insubstantial, repetitive book. It compares and equates mystical experiences induced by psychedelics to other types of mystical states. Hardly earth-shattering. Not much here beyond what Leary has said. A very slim volume. clark was part of the famous Good Friday Experiment with Pahnke and Leary.