In Cosmopolitan Justice1 Moellendorf carries on the work begun by theorists such as Charles Beitz and Thomas Pogge,2 further developing a cosmopolitan model of justice. Like Beitz and Pogge, he too modifies the Rawlsian approach to support a model of global justice that is more focused on individuals rather than states and proposes much bolder principles that are to define just interaction at the international level. Moellendorf also goes further than either of these theorists has hitherto gone in showing how a cosmopolitan model of justice could actually be applied to a range of pressing problems of global justice (including immigration, protectionism, justified intervention, debt cancellation, and dealing with the costs of global warming) and this is one of the key strengths of the book. With the exception of justified intervention, I will not discuss these applications here, though Moellendorf’s treatments of all these issues contain insights worthy of more attention. Rather, my focus in this paper will be on some central theoretical aspects of what cosmopolitan justice demands of us.