one of the bibles of the game
Doyle Brunson's "Super System - A Course in Power Poker" is probably the most famous of all poker books. Written back in the '70s, it originally sold for $100. Since then Brunson has frequently said he wishes he'd never written it, as it gave away too many of his trade secrets. Certain aspects of the book are a little dated (e.g. no mention of double blinds in the Hold 'Em section), but it's rightfully still considered a "must read" for serious poker players.
Doyle Brunson is actually only one of six authors, each covering a different poker variation. Brunson has the largest section - on No Limit Hold 'Em. Bobby Baldwin wrote the chapter on Limit Hold 'Em, Mike Caro discussed Draw Poker, Joey Hawthorne covers the varieties of Lowball, David Reese is the co-author for Seven Card Stud, and David Sklansky wrote about High-Low Split. It all ads up to 600+ pages of poker knowledge, including an enormous glossary and about 50 pages of statistics and probabilities.
It's enormous, it's full of valuable information about a large number of types of poker, and it features some great stories from Doyle Brunson. Like just about every other poker book you'll want to tailor the information to your own style (Brunson's theories will seem slightly maniacal to some), but Super System - A Course in Power Poker should be on your bookshelf.