My latest read has been Kane & Wilder's The Way to Black Belt, which could have been a pretty lame, 'how to get your black belt quick and easy" book but was so much more. Knowing the authors there should be absolutely no doubt. This is an excellent guidebook for beginners written by two guys who have been there and done that. Did I say, "for beginners?" Instructors can get a lot out of this book too!
In particular, I really enjoyed Chapter 4 - Understand Strength versus Skill, Chapter 5 - Practice a Little Each Day, and Chapter 7 - Know How to Work Through Injuries.
You'll find a ton of information in this book that will ease, if not speed your way to black belt regardless of what kind of martial art you are practicing.