Since the turn of the twenty-first century, the term communism has returned to the theoretical and historical agenda with a striking force and a surprising novelty. In a wide range of fields of knowledge, the questions of the actuality and the history of the world communist movement, the theoretical tendencies of communist thought, and the current political possibilities of new developments of communism have been revisited and addressed anew. We can only be struck by the degree to which it now seems that communism, far from the dead end of the twentieth century it was long assumed to be, may be something profoundly of the twenty-first century, an idea and field of concepts whose time has come. But what is also striking is the link between this return of communism and its site of return: the field of “critical theory.” What makes this site peculiar and remarkable is that it too has been in a long retreat since the 1980s in the fields of knowledge production. Theory’s impulse toward the politicization of knowledge, the immanent critique of the university, and its inherent globality, the fact that theory has long provided a common language beyond the regime of national language, has been the target of an intense reconquest by institutional neoliberalism, conservative politics, and positivist knowledge work. Yet it is no surprise that the return of the communist idea—and the new developments of revolutionary politics around the world in recent years—should exert a decisive force on the character and function of theory itself. But we ought to also emphasize that this theoretical conjuncture—the historical moment of the emergence of a communist critical theory—corresponds to a real situation of new political significations, a new historical and social sequence.