The Illuminatus! Trilogy by Robert Shea & Robert Anton Wilson

If you want to feel just that much weirder about the world, this mind-bending romp is for you.  Three books in one, so you don't have to chase around after the rest of the trilogy.  Recommended!  A cult classic.

It was a deadly mistake.  Joseph Malik, editor of a radical magazine, had snooped into rumors about an ancient secret society that was still alive and kicking.  Now his offices have been bombed, he's missing, and the case has landed in the lap of a tough, cynical, streetwise New York detective.  Saul Goodman knows he's stumbled onto something big -- but even he can't guess how far into the pinnacles of power this conspiracy of evil has penetrated.

Filled with sex and violence–in and out of time and space–the three books of The Illuminatus are only partly works of the imagination. They tackle all the coverups of our time–from who really shot the Kennedys to why there’s a pyramid on a one-dollar bill.