This book can answer it. An incredible overview of the science of resistance training is presented, with a summary of all of the scientific research done for years and years on the subject. If you are looking for the deeper meaning of resistance training concepts and want to know how and why they work, then this is the book for you. If you are a weekend trainer with no education outside of short little seminars and conferences, then you will not enjoy this book. A backround in exercise physiology as well as a thorough understanding of anatomical terminology is definately reccomended. But for those who know their exercise physiology, then this book is a great expansion into the science of resistance training.
If you enjoyed this book, other reccomendations would be "Science and Practice of Strength Training" by Vladimir M. Zatsiorsky and "Supertraining" by Mel C. Siff. "Serious Strength Training" by Tudor Bompa may also be of interest. All of these books are great for those who wish to dive into the deeper level of training. But if you're looking for superficial information, exercise ideas, home gym type stuff, then these books are not for you. These are designed for health professionals, not weekend warriors. Be prepared for science and technical terminology.