This is the first introductory survey of western twentieth-century music to address popular music, art music and jazz on equal terms. It treats those forms as inextricably intertwined, and sets them in a wide variety of social and critical contexts. The book comprises four sections - Histories, Techniques and Technologies, Mediation, Identities - with 16 thematic chapters. Each of these explores a musical or cultural topic as it developed over many years, and as it appeared across a diversity of musical practices. In this way, the text introduces both key musical repertoire and critical-musicological approaches to that work. It historicises music and musical thinking, opening up debate in the present rather than offering a new but closed narrative of the past. In each chapter, an overview of the topic''s chronology and main issues is illustrated by two detailed case studies.