Now that the Cold War has ended and poverty, environmental crises and nationalist demands loom large in world affairs, what is international justice? Are international agents ever likely to be just, and under what conditions? This book considers answers to these questions as found in the modern tradition of political philosophy - the tradition of Hobbes, Kant, Fichte, Hegel, Mill and Marx - and in contemporary writings about international justice and world order. One of the primary aims of the book is to determine the implications for international justice of the debates between cosmopolitans and communitarians. Is a well-grounded, universally acceptable theory of international justice possible, and if so, what social relationships should a just world promote? The book develops a theory of international justice and a conception of a just world which take as basic a respect for individual freedom and differences among communities.