John Cunningham Lilly was an American physician, neuroscientist, psychoanalyst, psychonaut, philosopher, writer and inventor. He was a member of a group of counterculture thinkers that included Timothy Leary, Ram Dass, and Werner Erhard, all frequent visitors to the Lilly home. He often stirred controversy, especially among mainstream scientists.

Psychonautics refers both to a methodology for describing and explaining the subjective effects of altered states of consciousness, including those induced by meditation or mind-altering substances, and to a research cabal in which the researcher voluntarily immerses themselves into an altered mental state in order to explore the accompanying experiences.