When a club player decides he wants to raise his rating, he typically looks to improve his middlegame or endgame understanding. Often, however, the true secret to improvement lies not in studying additional chess material but in learning a more powerful thinking process. The Improving Chess Thinker provides representative thought processes from all classes of chess players, highlights the differences between these levels, and provides insight to help players raise their thinking process to the next level.
Great kick in the pants for this casual "Hope Chess" player to drop the shenanigans and play "Real Chess". I haven't read many chess books, but thought the de Groot exercises and documented protocols across the ratings spectrum were very insightful.
(Just realized there's an updated and expanded version...)