Throughout the history of Western political thought, the creation of a world community has been seen as a way of overcoming discord between political communities without imposing sovereign authority from above. Jens Bartelson argues that a paradox lies at the centre of discussions of world community. The very same division of mankind into distinct peoples living in different places which makes the idea of a world community morally compelling has also been the main obstacle to its successful realization. His book offers a philosophical and historical analysis of the idea of world community by exploring the relationship between theories of world community and changing cosmological beliefs from the late Middle Ages to the present.