This introductory chapter sets out the theoretical framework for this book which revisits the generation of avant-garde post-war composers associated with the golden age of musical modernism. By focusing on how the works of these composers were understood and perceived by contemporary listeners in the golden age of stereo hi-fi receivers in the 1950s and 1960s, it explores the ways this reception was mediated through the technology of sound reproduction that ushered in hi-fi record culture. It contends that consumer-oriented sound technology formed a prism through which listeners assimilated what was billed as “music of their time.” This prism was fashioned out of listeners’ formative experiences with new kinds of technologically mediated listening. The chapter includes a literature review that emphasizes connections between musicology, popular music studies, sound studies and science and technology studies, as well as introducing key concepts such as Mark Katz’s “phonograph effects” and Roland Barthes’s “simulacrum.”