Ralph Humphrey Guenther Metzner was born in Berlin, Germany on May 18, 1936. He received a degree from Queen's College, Oxford and a Ph.D. from Harvard University in 1962. While a graduate student at Harvard, he worked with Timothy Leary and Richard Alpert on their research exploring therapeutic and other uses for LSD, psilocybin, and similar hallucinogens. In 1964, the three collaborated on The Psychedelic Experience: A Manual Based on the Tibetan Book of the Dead. Metzner became a psychotherapist and in 1975 joined the faculty of what was then the California Institute of Asian Studies. He taught there for 31 years and served as academic dean from 1977 to 1989. He took emeritus status in 2006. He wrote numerous books including Maps of Consciousness, The Unfolding Self: Varieties of Transformative Experience, Green Psychology: Transforming Our Relationship to the Earth, and The Expansion of Consciousness. He died from idiopathic pulmonary fibrosis on March 14, 2019 at the age of 82.