Timothy Leary

American psychologist who transformed from a Harvard researcher into the leading public advocate for LSD — becoming the defining countercultural figure of the 1960s and coining 'Turn On, Tune In, Drop Out.'

Harvard Psilocybin Project: early systematic study of psilocybin's psychological effects. Turn On, Tune In, Drop Out: the rallying cry of the counterculture — using psychedelics to achieve altered consciousness and reject mainstream society. The Psychedelic Experience (with Richard Alpert): a guide to LSD trips based on the Tibetan Book of the Dead. Credited (and blamed) for popularizing LSD widely.