“Don't believe that jazz about there's nothing you can do, "turn on and drop out, man" — because you've got to turn on and drop in, or they're going to drop all over you.”

Source: Someone Like You (1998)

Source: Turn On, Tune In, Drop Out

Deeper Thoughts : All New, All Crispy (1993), Hachette Books, ISBN 1-56282-840-1

Grace Slick, and Leary are both quoted in the Infected Mushroom song "Drop out" on the EP Deeply Disturbed (2003), but only the final portion actually quotes Leary.
Misattributed

On his living at a Zen center, as quoted in Los Angeles Times (24 September 1995)

A Trip with Paul Kassner <!-- Politics of Ecstasy 1999 p. 215 -->
The Politics of Ecstasy (1968)
Context: My advice to myself and to everyone else, particularly young people, is to turn on, tune in and drop out. By drop out, I mean to detach yourself from involvement in secular, external social games. But the dropping out has to occur internally before it can occur externally. I'm not telling kids just to quit school; I'm not telling people to quit their jobs. That is an inevitable development of the process of turning on and tuning in.

Republican presidential candidate debate, Johnston, Iowa, 2007-12-12
Republican Debates

Vol. XI, p. 242
Posthumous publications, The Collected Works
Context: When death comes, it does not ask your permission; it comes and takes you; it destroys you on the spot. In the same way, can you totally drop hate, envy, pride of possession, attachment to beliefs, to opinions, to ideas, to a particular way of thinking? Can you drop all that in an instant? There is no “how to drop it”, because that is only another form of continuity. To drop opinion, belief, attachment, greed, or envy is to die — to die every day, every moment. If there is the coming to an end of all ambition from moment to moment, then you will know the extraordinary state of being nothing, of coming to the abyss of an eternal movement, as it were, and dropping over the edge — which is death. I want to know all about death, because death may be reality; it may be what we call God — that most extraordinary something that lives and moves and yet has no beginning and no end.