Understanding Exposure, 3rd Edition: How to Shoot Great Photographs with Any Camera by Bryan Peterson

This book is an incredibly helpful resource on how to take photography beyond your point and shoot camera. I found the sections on which aperture to choose and how to meter your shots correctly especially helpful, although I know the whole thing gave me both the theory and the practical knowledge necessary to  improve my photography skills. I would recommend that any photography enthusiast buy this book. The beautiful photographs used to illustrate the points are a benefit.