I love to work out. Always have. Was in all the sports throughout school. And was always interested in anatomy/physiology and how all that works when it comes to exercise.
I was working on putting together an exercise routine and discovered this great book, Strength Training Anatomy Workout.
It's a great book. It has lots of drawings that show you which muscle is being worked with which exercise. It also has a bunch of exercises. It discusses the reasoning behind putting a routine together, how often to work out, in which order to work the different muscles, and so on.
Really useful book if you're into exercise. Frederic Delavier, the author also has a bunch of other related books. He does all the drawings. Amazing!