[sedachv]

Deleuze and Guattari's Anti-Oedipus. It changed the way I think about sanity and insanity, my model of the mind and motivational forces, the "big-picture" view of economics, how government works, how psychiatry works, and the way media affects us.

IMO it's treatment of desire (from a negative (lack) to a positive (thought production machine); relationship of desired object to its platonic object desire; how desire is generated) is a great framework for advertising and product development.