This study offers a panoramic survey of musical thought in the 18th century and, at the same time, a close analysis of the important theoretical topics of the period. The result is one of the most comprehensive accounts ever given of the theory behind the music of late Baroque and early Classical composers from Bach to Beethoven. While giving pre-eminent theorists their due, Joel Lester also examines the works of over 100 18th and 17th century writers to show how prominent theories were received and applied in actual teaching situations. Beginning with the influence of Zarlino and 17th century theorists, Lester goes on to focus on central traditions emerging from definitive works in the early 18th century: species counterpoint in the writings of Fux; thorough-bass as presented by Niedt and Heinichen; Rameau's harmonic theories; and Mattheson's views on melodic structure. The author traces the development and interactions of these traditions over the remainder of the century, through the writings of Albrechtsberger, C.P.E. Bach, Kirnberger, Koch, Marpurg, Martini, Nichelmann, Riepel and many others. This historical overview is leavened throughout with lively accounts of individual composers grappling with theoretical issues - Haydn's careful study of Fux's treatise, Mozart's instructions on harmony to his composition students, Beethoven's own student exercises. The lnks between various theoretical traditions, the pervasive influence of Rameau's harmonic thinking, and the harmonic theories of Koch are just some of the numerous topics given their first full treatment here. Many of the theorists Lester cites are either unknown or often misunderstood today.