Aaaaaannd....now I know where Inverarity's livejournal username and picture come from. I guess you're a real Pynchon fan, eh Inverarity?
Mercury Shrugged: The Crying of Lot 49, by Thomas Pynchon
One summer afternoon, Mrs. Oedipa Maas came home from a Tupperware party whose hostess had put perhaps too much kirsch in the fondue to find out that she, Oedipa, had been named executor, or she supposed executrix, of the estate of one Pierce Inverarity, a California real estate mogul who had once lost two million dollars in his spare time but still had assets numerous and tangled enough to make the job of sorting it out more than honorary. Oedipa stood in the living room, stared at by the greenish dead eye of the TV tube, spoke the name of God, tried to feel as drunk as possible. But this did not work. She thought of a hotel room in Mazatlan whose door had just been slammed, it seemed forever, waking up two hundred birds down in the lobby; a sunrise over the library slope at Cornell University that nobody out on it had ever seen because the slope faces the west; a dry, disconsolate tune from the Fourth Movement of the Bartok Concerto for Orchestra; a whitewashed bust of Jay Gould that Pierce kept over the bed on a shelf so narrow for it she'd always had the hovering fear it would someday topple on them.
Pynchon is somewhere on the weirdness spectrum between Vonnegut and William S. Boroughs. The Crying of Lot 49 --the title refers to the auctioneering of a set of postage stamps--is probably the best introduction to Pynchon there is. It's only 150 pages; most of his work is much, much longer, and all of it is solidly packed with dense themes, metaphors, puns and cultural references both ancient/scholarly and modern/hip, and everything in between. The quoted part above is the first paragraph of the book, and Oedipa the heroine can't so much as look at a billboard without similar language.
The estate of which Oedipa is executor belonged to an eccentric billionaire (is there any other kind?) who owned pieces of, I mean, everything, including a factory that made charcoal cigarette filters out of the bones of American WWII casualties. He also had a stamp collection that includes "Lot 49", a set of clever forgeries containing a distinctive post-horn symbol that suddenly shows up everywhere Oedipa goes. She finds it as graffiti on a bathroom wall. She visits an old folks' home that is part of the estate's holdings, and the old guy in the lounge just happens to have relevant memories about his grandfather the mail carrier. She goes to see a production of a Jacobean revenge play, and a line of text gets her attention. She meets people with suggestive names like "Mike Fallopian" and "Genghis Cohen". Random bar conversations reveal important information.
All of these random encounters seem to point to the existence of a secret libertarian courier service in competition with the Post Office, that has been around since the 17th century or longer, that uses stamps like the ones in Lot 49, and that kills people who get in their way. Or else someone is putting an elaborate hoax on Oedipa. Or maybe she's on drugs and hallucinating it all--except that Bad Things suddenly begin to happen to the people who make up Oedipa's meager coping network--her husband, her therapist, the people she's confided in about the phantom post office. And the book ends just as Owedipa is sitting down to see who will bid on the stamps at the auction.
The book may be an example of what Robert Anton Wilson called "guerilla ontology". It includes hoaxes and misdirection on purpose, to teach people not to just blindly accept whatever they read. It has something existential to say about modern (in the 1960s, when the book was written) life and culture in California, and maybe about the meaning of life in general, about things not being what they seem, and about how we know anything and how we cope with the uncertainty about what we think we might not know after all. Very high recommendations.