Leary believed LSD showed therapeutic potential for use in psychiatry. He popularized catchphrases that promoted his philosophy such as "turn on, tune in, drop out" (a phrase given to Leary by Marshall McLuhan); "set and setting"; and "think for yourself and question authority". He also wrote and spoke frequently about transhumanist concepts involving space migration, intelligence increase and life extension (SMI²LE), and developed the eight-circuit model of consciousness in his book Exo-Psychology (1977). During the 1960s and 1970s, he was arrested often enough to see the inside of 29 different prisons worldwide. President Richard Nixon once described Leary as "the most dangerous man in America". Early life and education Leary was born in Springfield, Massachusetts, the only child of an Irish-American dentist who left his wife Abigail Ferris when Leary was 13. He attended the College of the Holy Cross in Worcester, Massachusetts from September 1938 to June 1940.
• Outside the Box