After Modern Jazz rethinks the history of the jazz avant-garde in dialogue with aesthetic philosophy, critical theory, and African American history. It focuses on the conjuncture of the late 1960s and 1970s as a point from which to revise canonical narratives of jazz history, and connects music and aesthetics to the political economies of cultural production and the transnational politics of decolonization. Part I of the dissertation develops an ideology critique of jazz historiography, posing an explanation for the absence of 1970s experimentalism from jazz history in the unsymbolizable historical break of “1968”, and reframing the emergence and development of “jazz discourse” in the 20th century as a hegemonic struggle in which “jazz” knitted together contradictory ideological and racial projects. A reinterpretation of Theodor Adorno’s notorious attack on jazz suggests its continuing relevance for theorizing the conjunction of critical theory and improvisation. Part II of the dissertation analyzes several key musical and counter-ideological projects of the avant-garde from 1965-1977. The jazz panels of the mid-1960s were a public stage for the performance of a masculinist black-white political dialectic, and musician Archie Shepp’s politics of culture emerged within and against the silences and foreclosures of the historiography of slavery in the U.S.  The jazz avant-garde displaced the American popular song as the raw material of jazz improvisation with a new constitutive outside: a variety of compositional languages and an undifferentiated field of “world music.” Amid the contradictory cultural politics of African decolonization and revolutionary movements, the performance of African American musicians at the 1969 Pan-African Festival of Arts and Culture in Algiers offers a perspective on transnational and diasporic cultural formation. Finally, the dissertation interprets the mid-1970s popularity of duo improvisation as an accommodation to the conditions imposed on artistic practice by an emerging regime of neoliberalism. While the improvisatory music made in the 1970s explore the sensory terrain of a politics that can oppose and resist neoliberalism, those resources for resistance are densely encoded within the music’s aesthetic project: the duo, along with other avant-garde musical aesthetics, constitute in Adorno’s terms a “self-unconscious historiography of their epoch.