I have been in the industry for over 25 years. I always make it a point to go back and look at my training manuals now and again. It really refreshes my memory.
I have one book in particular I like in my library. It is clear and simple. It also has a companion cd-rom included. It is more about how the body moves rather than particular exercises.
‘Fitness Professionals Guide to Musculoskeletal Anatomy and Human Movement’, by Lawrence A Golding and Scott M. Golding (father and son).
Good Luck. Let me know if you end up buying it!