This book is composed of a set of chapters contributed by past and present collaborators of the Nobel laureate Sir Andrew Huxley, covering the areas of muscle research to which he has made major contributions. The purpose of the book is to discuss the way that muscle works, asking questions at a fundamental level about the molecular basis of muscle tone production and muscle contraction. The majority of the chapters are concerned with muscle physiology and the relation between structure and function. The process of activation of muscle is dealt with, together with the mechanism of contraction itself. Although most of the book concerns itself with vertebrate skeletal muscle, several of the chapters deal with cardiac muscle. The book also features two introductory chapters discussing Sir Andrew's achievements in both nerve and muscle physiology. All those interested in the structure and function of muscle, or cell motility in general, will wish to read this book.