I have long recommended Bryan Petersons book "Understanding Exposure" as an excellent guide for newer photographers having trouble getting a grip on the exposure triangle, and while he is heavy into manual exposure, the guide is useful for any mode of photography.

I just came across another book by Peterson called "Exposure Solutions". It looks to have been on the market for a couple of years now but I had never seen it or even heard of it. Last night I read the book and was impressed with the concise coverage on how to handle many difficult exposure situations. Much of the book is somewhat a re-hash of techniques in his previous guides, but the smaller size and more intent information makes this book a very good read for anyone who has had problems with particular exposures. If you can get your hands on a copy, it is well worth the $20 price. A little cheaper on Amazon.