For books on how to brew: "How to Brew" by John Palmer. Brewing knowledge more concentrated than any other source I know.
If you've already got "How to Brew" then I'd recommend "Radical Brewing" by Randy Mosher. Brewing wisdom more concentrated than any source I know. Radical brewing covers brewing history and historical styles, recipes, and how to and how not to use TONS of sugars, fruits, herbs, & adjuncts. There's even a chapter on mead. Randy Mosher really seems to understand the flavor impacts to everything that he does and his writing style makes it easy for you to download his knowledge to your brain.
If you like to brew Belgian styles then "Brew Like a Monk".
Adam
