How can we determine what are just boundaries or just criteria for inclusion or exclusion in contemporary states, nations, peoples, or other 'communities of justice'? As Barbieri demonstrates, recent theories of justice have failed to grapple squarely with this fundamental problem, either wholly ignoring it, or approaching it, inadequately, in terms of distributive or commutative justice, or simply declaring the problem insoluble. Developing a clear understanding of the peculiarities of constitutive justice, Barbieri contends, is a task that has important implications for political philosophy as it bears on topics such as citizenship, migration, multiculturalism, self-determination, and the drafting of new constitutions. To this end, Constitutive Justice critically discusses some present approaches that promise to shed light on constitutive questions involving inclusion and the ethics of boundaries; provides an analysis of some of the central topics that plausible normative theories of constitutive justice will need to address; and develops the author's own constructive account.