As a graduate student at Harvard (where he received a Ph.D. in clinical psychology), he worked with Timothy Leary and Richard Alpert (later Ram Dass) on the Harvard Psilocybin Projects. He co-wrote The Psychedelic Experience and was editor of The Psychedelic Review. Since 1975, he has been a professor of psychology at the California Institute of Integral Studies. He is also president of the Green Earth Foundation, a non-profit organization dedicated to reconnecting humans and the environment. The author of over a dozen books, Dr. Metzner maintains a part-time psychotherapy practice and conducts numerous workshops on consciousness transformation, both nationally and internationally.