This book introduces a variety of topics related to muscles and the energetics of work including: comparative anatomy, physiology, basic mechanics of simple machines, history of machines that use muscles, etc. The style is engaging, lively, and clear. Many concepts, some of them complex, are described in a way that non-specialists can understand, although, occasionally, the reader may have to work a bit. It helps if you have some previous knowledge of physiology but it isn't absolutely necessary. If you would like to learn about insect muscles, Roman catapults, and row boats, buy this book.