A survey of Debussy, Stravinsky, Bartók, Varèse, Ives, and other composers who transformed music in Europe and the United States before World War II, as well as prominent post-war figures such as Lutoslawski, Messiaen, and Carter. Topics include the changing role of the composer in society, relationships to literary and visual modernism, the evolution of musical technology, and the composer's dialogues with vernacular music and other traditions.