For the basics on how to brew - How to Brew by John Palmer - also available for free in an online format http://www.howtobrew.com/intro.html
For insight on recipe formulation of classic beer styles (although a little dated now) - Designing Great Beers by Ray Daniels
For inspiration and formulation of non-classic styles using "non-traditional" ingredients- Radical Brewing by Randy Mosher
These books are good, but if you have never brewed before..... "The Complete Joy Of Homebrewing" by Charlie Papazian is by far the most accessible and well though out book for new homebrewers. It has been revised a few times over the years and is still in print and readily available.
Even though I have been homebrewing for going on 38 years, I _still_ refer to this one every now and again for information. Papazian keeps things simple, yet gets technical when necessary, and explains how to make many different types of beer without getting too bogged down by the current and ever increasing dogma regarding "beer styles". (there are only really a few basic "styles"...followed by dozens of different variations on the theme).
Definitely a book worth looking into.
"Brewing Classic Styles" is another good one. It has at least one award-winning recipe for every style of beer classified by the American Homebrewing Association, from Bud clones to Flanders Sour Ales to Imperial Stouts.
After you get into brewing a little bit, check out "Brew Like A Monk" for a popular and informative look into Belgian-style beers. If you ever want an in-depth look at the nitty-gritty details of making beer, check out "Principles of Brewing Science" by George Fix.