Book Recommendations by Homer Franck
Highest Rating to date is 1636

Chess books are not important per se but only as they support a chess players study program. Everyone should have a clear idea of why he is reading a particular book and how he expects that book to contribute to his chess knowledge.  In other words, books will not make you a better player. You become a better chess player by gaining a clearer awareness of how you approach each game you play and how to learn from that game. To play a game of chess I believe you need:

Thinking technique, Training and some knowledge of common patterns and motifs;

in that order of importance.  There are many, many books focused on the "common patterns" area (I  include opening books here) and I don't think it matters a whole lot which ones you pick in this area.

THINKING TECHNIQUE

Recognizing this as the most important, but also the most highly personal and subjective area here are the books I have found most beneficial with a brief reason for each:
Chess Master ...at any age, Rolf Wetzell Increasing mental images using flash cards. How to make flash cards is fully explained. The KEY is that the flash cards are based on your own games. You compose "grabber phrases" which you use to formulate and reinforce images and concepts that relate directly to your style and technique. HIGHLY RECOMMENDED.
The Search For Chess Perfection C.J.S. Purdy A specific thinking technique described step-by-step: you will have to adapt and internalize it according to your own style. There are also a number of other articles on specific chess elements originally published in Australian chess magazines: e.g. conditions contributing to a combination.
Think Like a Grandmaster Alexander Kotov Excellent discussion of "how to analyze"; shows that grandmasters are human, too.
How to Reassess Your Chess Jeremy Silman A manual of "motifs". As with Purdy, a specific thinking technique is formulated.
Tactics In The Grunfeld Gannady Nesis Recommended for the vocabulary it will add to you chess thinking: pin, enticement, deflection, interference, demolition, opening and clearing lines, exploiting the Back Rank.
Secrets of a Chess Master Rick Melton Good comments on personal style and technique: e.g. KUFTEG - King Up For The Endgame.

TRAINING

FIDE Master Igor Foygel told us that "1 hour per day spent analyzing positions to find the best move" was the best way to improve your game. Here are three excellent examples:

Combination Challenge Lou Hays and John Hall 1154 positions arranged according to tactical theme: e.g. double attack.
Chess Training Pocket Book GM Lev Alburt 300 most important positions and ideas. The explanations are excellent!
Test Your Chess IQ August Livshitz 56 tests of 8 positions each arranged according to theme. This is hard work. There is a "progress chart" that, hopefully, will document your improvement.
These are just very good examples. The important thing is the "hour per day" of personal training. To all of this I would add Chessbase Magazine, a series of CDs for those who like the efficiencies of training on a computer. I cannot recommend Chessbase Magazine too highly. This deserves a thorough review in Chess Horizons.