Timothy Francis Leary (October 22, 1920 – May 31, 1996) was an American psychologist and author known for his strong advocacy of psychedelic drugs. Evaluations of Leary are polarized, ranging from bold oracle to publicity hound. He was "a hero of American consciousness", according to Allen Ginsberg, and Tom Robbins called him a "brave neuronaut".As a clinical psychologist at Harvard University, Leary worked on the Harvard Psilocybin Project from 1960 to 1962. He tested the therapeutic effects of lysergic acid diethylamide (LSD) and psilocybin, which were still legal in the United States at the time, in the Concord Prison Experiment and the Marsh Chapel Experiment. The scientific legitimacy and ethics of his research were questioned by other Harvard faculty because he took psychedelics along with research subjects and pressured students to join in. However, the claim that Leary pressured unwilling students was denied by one of Leary's students, Robert Thurman. Leary and his colleague, Richard Alpert (who later became known as Ram Dass), were fired from Harvard University in May 1963. Many people of the time only learned of psychedelics after the Harvard scandal.Leary believed that LSD showed potential for therapeutic use in psychiatry. He used LSD himself and developed a philosophy of mind expansion and personal truth through LSD. After leaving Harvard, he continued to publicly promote the use of psychedelic drugs and became a well-known figure of the counterculture of the 1960s. He popularized catchphrases that promoted his philosophy, such as "turn on, tune in, drop out", "set and setting", and "think for yourself and question authority". He also wrote and spoke frequently about transhumanist concepts of space migration, intelligence increase, and life extension (SMI²LE). Leary developed the eight-circuit model of consciousness in his book Exo-Psychology (1977) and gave lectures, occasionally billing himself as a "performing philosopher".During the 1960s and 1970s, he was arrested 36 times worldwide. President Richard Nixon once described Leary as "the most dangerous man in America".