Timothy Leary was an American psychologist and writer, known for his advocacy of psychedelic drugs. Born in 1920, he gained fame in the 1960s as a proponent of using LSD for therapeutic purposes and exploring consciousness expansion. Leary's controversial research and countercultural activities led to clashes with authorities, resulting in his imprisonment. Despite this, he remained a influential figure in the field of psychology and continued to promote his ideas of personal liberation and spiritual enlightenment until his death in 1996.