What if the history of Frankfurt School Critical Theory were told not through its academic inheritance by German philosopher Jürgen Habermas but through its grassroots reception and transformation among New Left actors in the 1960s? This book tells that story by retracing how, amidst anticolonial struggle and global youth revolt, a transatlantic generation of student organizers like Angela Davis and Hans-Jürgen Krahl revived the Frankfurt School's anti-fascist archive to aid in their struggles for Third World liberation and peace in Vietnam, an autonomous university, a feminist family, an end to global capitalism, and an abolitionist future. Against histories of Critical Theory that entrench its academization, Sebastian wagers that the Frankfurt School's New Left generation offers the strongest case for maintaining Critical Theory as a living tradition of social critique in service of emancipation.