I am a physical Therapist and I have never seen such a great book showing how muscles worktogether and how training works. I actually used this example in an exam about teaching adults . So I highly recommend this book to people who go to gyms and exercise on their own. This book shows, like a see-through body, how muscles contract and let go when you exercise them. It shows which parts of body actually really work and which parrts are just holding. It creates an awareness about the physical holistic system, like all things work together. It also lets people understand, that muscles work only for joints, to move joints, and that muscles can only contract and nothing else.The book is easy to understand for everybody.