This book is about biomechanics: it compares the mechanical solutions used by people and by nature. There are huge differences between the two, and perhaps something we could learn from the nature. Of course, that's what people have tried to do for thousands of years, with varying success - flying is probably one of the best examples of cases where not emulating nature lead to success.
Vogel has plenty of material and while it all is rather interesting in theory, I found the book somewhat boring and finished it by browsing through it rather swiftly. The dry text just couldn't hold my interest. I wouldn't recommend the book unless you're really interested in the topic. This isn't one of those excellent popular science books that makes you interest in its topic: I believe you need to have previous interest in mechanics to make Cat's Paws and Catapults work. (Review based on the Finnish translation.)