I bought a book recently that I think is wonderful for people at all levels of photography. It's Bryan Peterson's latest one. I have Understanding Exposure, and I would recommend that one first, but this one seems to be a compilation of parts of all of his books. I haven't had a chance to read it, but I have looked through it and can tell that it is going to be another book I love. This is the link at Amazon:
Amazon.com: Bryan Peterson's Understanding...