The thirteen essays by Allen Buchanan collected here are arranged in such a way as to make evident their thematic interconnections: the important and hitherto unappreciated relationships among the nature and grounding of human rights, the legitimacy of international institutions, and the justification for using military force across borders. Each of these three topics has spawned a significant literature, but unfortunately has been treated in isolation. In this volume Buchanan makes the case for a holistic, systematic approach, and in so doing constitutes a major contribution at the intersection of International Political Philosophy and International Legal Theory. A major theme of Buchanan's book is the need to combine the philosopher's normative analysis with the political scientist's focus on institutions. Instead of thinking first about norms and then about institutions, if at all, only as mechanisms for implementing norms, it is necessary to consider alternative 'packages' consisting of norms and institutions. Whether a particular norm is acceptable can depend upon the institutional context in which it is supposed to be instantiated, and whether a particular institutional arrangement is acceptable can depend on whether it realizes norms of legitimacy or of justice, or at least has a tendency to foster the conditions under which such norms can be realized. In order to evaluate institutions it is necessary not only to consider how well they implement norms that are now considered valid but also their capacity for fostering the epistemic conditions under which norms can be contested, revised, and improved.