Just received a new purchase from Amazon.com..."Chess Exam and Training Guide" by Igor Khmelnitsky. Bought it because it sounded good, very well reviewed on Amazon, and because it sounded like it would help me pinpoint weaknesses in my game. Gotta say, after working through the first twenty puzzles, that it's pretty humbling. I'm scoring about 50% on the tests, which evaluates my playing level much lower (about 1200) than my tournament performance...to say nothing of my rating on Chess.com, which must be vastly inflated. I think so far this book was a good investment, and would already recommend it. Just be prepared to suffer.