+1 for How to Brew
Also, for reading it in order to get more from this forum. I feel Palmer does a good job of noting different opinions on procedures/philosophies (i.e. Secondary fermentation) than when you read opinions of others on here, you've got a better idea about where they may be coming from and the merits of their methodology.
I just began Radical Brewing and have really enjoyed it, but to be honest I think I'd enjoy it less without previous knowledge I received from How to Brew. Maybe it's because I enjoy playing with numbers, but Palmer gave me the confidence to create my own recipes and know that in the end, I'll still have beer (almost) no matter what I do/don't do.