From the “red years” that followed the social explosion of May '68 into the first decades of the 21st century, Alain Badiou and Toni Negri have produced two imposing and consequential bodies of philosophical writing, while never abandoning their commitment to a militant politics of equality. The essays collected in this book tackle multiple dimensions of their work—from ontology to biopolitics, from art to violence, from the theory of capitalism to the challenge of counter-revolution. But all of them are also efforts to explore and answer a single question: What does it mean to be a communist in philosophy?