Defining the principles of justice that ought to govern the global economic and political sphere is one of the most urgent tasks that contemporary political philosophers face. But they must also contribute to working through the institutional implications of these principles. How might principles of global justice be realized? Must the institutions that aim to implement them be transnational, or can global justice be attained within the context of the state system? Can institutions of democratic self-governance be imagined beyond the nation-state? These are just some of the questions that still face political philosophers even when issues of abstract principle have been addressed. This volume establishes a dialogue between philosophers working at all levels of abstraction. Some of the authors are concerned with the grounds and scope of the obligations that bind the citizens and governments of rich countries to those of poorer nations. But many examine the question of how these obligations can be satisfied, both within existing institutional frameworks and beyond. Together their essays constitute a major contribution to the advancement of both the theoretical understanding and the practical requirements of global justice.