I've had a copy of Bass's book "Challenge Yourself" since college. One of our prof's suggest it, at one time.
Pretty much sums up the basic of training, diet or any thing else about gaining, and holding, lean muscle mass....without losing any of that muscle mass. I know he's written a lot of other book along this line, but just my view (for what it's worth) this book is a great introduction to logical and rewarding training. And for just about anyone, just starting out or even the advance trainer.
Good Luck.