In 1967, Leary spoke at the Human Be-In, a gathering of 30,000 hippies in Golden Gate Park in San Francisco and phrased the famous words, "Turn on, tune in, drop out".
On this lengthy album, Leary can be heard speaking in a monotone soft voice on his views about the world and humanity, describing nature, Indian symbols, "the meaning of inner life", the LSD experience, peace, and many other issues.
Leary added McLuhan "was very much-interested in ideas and marketing, and he started singing something like, 'Psychedelics hit the spot / Five hundred micrograms, that's a lot,' to the tune of a Pepsi commercial of the time.
[4]Turn on, Tune in, Drop out is also the title of a book (ISBN 1-57951-009-4) of essays by Timothy Leary, covering topics ranging from religion, education, and politics to Aldous Huxley, neurology, and psychedelic drugs.
"[6] During his last decade, Leary proclaimed the "PC is the LSD of the 1990s" and re-worked the phrase into "turn on, boot up, jack in" to suggest joining the cyberdelic counterculture.