This book reveals the spectacular degree to which biological macromolecules, particularly proteins, move as they go about their business. The first chapters of the book deal with methods and computer algorithms, both subjective and objective, that have been historically used to analyze the changes when two alternate conformations are known. The following chapters present classification schemes to catalogue these changes. The final chapters discuss in detail several notable examples of dynamic protein motion by specialists in those areas. This book includes an interactive multimedia CD-ROM, which depicts the motions of seven proteins in Molscript, c-alpha and CPK and describes the nature of their molecular hinge mechanisms.