Based on the author's successful book on the principles of protein structure, this book explains the general characteristics of proteins that underlie the very great variety of protein folding patterns observed in nature. It is profusely illustrated with superb computer graphics in full colour throughout the text. Most of the illustrations are stereo diagrams, which are stunning three-dimensional representations of protein structure. The book also introduces the use of the World Wide Web in bioinformatics. To suit the needs of courses, each chapter includes recommended reading, lists of useful web sites, traditional exercises, and a newly-introduced type of exercise called a weblem, for WEB-based probLEM.