Composers of modernist music frequently referred to technical, psychological and sociological theories of communication in their work, work which often addresses the very psychoacoustic and sociological foundations of musical practice. The compositions and theoretical writings that resulted themselves constitute a significant contribution to the understanding of musical communication. The chapter focuses on the ‘high modernism’ of the 1940–1960s, including examples from the work of Stockhausen, Pousseur, Babbitt and Cage, among others.