To date my favorite book is Ross Hoddinott's '
Digital Exposure Handbook' which covers:
1 The basics of exposure.
2 Exposure in practice.
3 Ambient light.
4 Flash light.
5. Filters.
6 Exposure in the digital darkroom.
Also his books on Filters & Macro Photography are good.
http://www.rosshoddinott.co.uk
http://www.pipress.com