In this edition, in addition to emendations made throughout the book, the chapters on Medieval, Renaissance, and Baroque art have been thoroughly revised and expanded. The chapters on the eighteenth, nineteenth, and twentieth centuries have been enlarged to accommodate matter from new studies and interpretations and are presented, we believe, with improved continuity and organization. There are, of course, corresponding increases in the number of illustrations. A new feature of considerable importance is the integration of color illustrations so that they are no longer bound in isolated groups, distant from their citations, but appear in sequence among the black-and-white illustrations.