Malcolm Campbell sums up the game of golf here in one book. There is everything from streching before your game to more advanced topics like course managemen. With just one time through the book I'll bet it helped me lower my score by two to three strokes per round, and when you already shoot in the low 80's thats not as easy to do. Buy the book!
much of the information I have heard before. If you haven't read many golf books this is a great one to start with. It is full of great suggestions from A-Z. For something a little more unique you might also check out Par Golf by Schnackenberg.