Understanding Exposure by Bryan Peterson.

I've read several photography books in addition to taking classes. Hands down this is the book I'd recommend if you aren't going to take a class for understanding the basics (and even the specifics) of exposure or if you just want a little more help understanding how aperture, shutter speed & iso work together. The author has an easy to understand and friendly style and uses an abundance of photographs to illustrate information, examples and points he's trying to make. All the photos have all the lens, shutter, and aperture setting info (old school EXIF data) to help you learn.

What I found most beneficial about the book was the real variety of situations his examples took place in. From all the lighting situations you can imagine to swimming pools, to frozen fields, to vineyards to city streets. Some other photography books I've read have used bizarre examples in situations that I could never actually imagine occurring so I had a hard time processing the information into something I could use.

Of course as I praise this book I should also point out that I almost read this book too late. Meaning that since buying my digital rebel xt a few weeks back I've learned infinitely more about the technical aspects of photography than I knew before. There is simply no replacement for hands on learning. That being said I still think this book is a great reference book for anyone looking to increase their understanding of exposure and the technical side of their photography. I firmly believe that Improvements in the technical side of your photography lead to great improvements in the artistic side of your photography as well.