Understanding Exposure: How to Shoot Great Photographs with a Film or Digital Camera (Updated Edition) Pretty much a must-have for beginners. Bryan Peterson explains exposure in an easy to understand, fun way.
Learning to See Creatively: Design, Color & Composition in Photography (Updated Edition) Another one of Bryan Peterson's gems for beginners.
Photographic Composition One of the best books I've read on this topic & I go back to it often.
Beyond Portraiture: Creative People Photography Beyond portraiture says a lot about approaching people and making timeless images of them. This book was a huge help when I began.
Understanding Close-up Photography: Creative Close Encounters with or without a Macro Lens Like photographing flowers & bugs? This one is for you. The best thing is that there are ways to do it without buying an expensive macro lens.