From the Preface: The field of chamber music has undergone consistent development since this book was first published eighteen years ago. Historical researchers have discovered many new facts and provided new insights into the earlier periods. A new generation of contemporary composers has introduced new styles and style elements into the field. The standard repertoire itself has been enlarged even as the sheer number of chamber-music performance and recording has increased. The second edition of this book seeks to reflect the increasing impact of chamber music on concert life everywhere. The chapters dealing with its growth to about 1730 have been completely rearranged, and much new material has been incorporated. Sections on composers treated sketchily or not at all in the first edition-notably Vivaldi and Boccherini-have been enlarged or added in the second. The very definition of chamber music has been broadened to include violin sonatas and cello sonatas, and many works in these categories have been discussed. The chapter on contemporary music has been rewritten and expanded to take into account the most recent developments. Finally, the bibliography has been enlarged to include the most important items that deal with chamber music and its composers. One omission may be noted in the second edition: the lists of chamber-music publications and recordings. Such lists are inevitably out of date even when they first appear; and the existence of comprehensive catalogues today makes the music and long-playing phonograph recordings generally available in any case.