This book places the radicalization of art music in early post-war France in its broader socio-cultural and political context. It pursues two general and intersecting lines of inquiry. The first details the stances towards musical conservatism and innovation adopted by cultural strategists representing Western and Soviet ideological interests at the onset of the Cold War. The second, which draws upon the commentaries of Theodor Adorno and Jean-Paul Sartre, recognizes that the Cold War generated a heightened political awareness amongst French musicians at the very time when the social relevance of avant-garde music had become the subject of widespread debate. The study considers the implications of the performance at L'Oeuvre du XXe siècle, an international arts festival staged in Paris in 1952 with the intention of discrediting socialist realism by means of two opposing musical types: neo-classicism (represented by Stravinsky's Symphony in C) and serialism (Boulez's Structures 1a).