I was wondering which book to buy; Robert Kennedy's Encyclopedia of Bodybuilding, or Schwarzenegger's new encyclopedia of Modern Bodybuilding. So as any reasonable person, I bough both. To my delight, BOTH of these books a great, and any of them would be a fine reference item. Arnold's book covers more body building as a whole, and talks more about the actual exercise and what they do to the muscles. It talks about all the aspects of amateur and professional bodybuilding, and has great photos. Robert Kennedy's book has a more magazine-like approach. It has about 100 chapters covering every aspect in detail and including topics and sub-topics, and gives you routines from the world's top body builders. If I was to buy 1 book only I would buy Arnold's book, because I think you can get better results by following his principles, but I definitely recommend Robert Kennedy's book also, because it has more of a scientific approach.