This is a book about the theory of the city or commonwealth, what would come to be called the state, in early modern natural law discourse. Annabel Brett takes a fresh approach by looking at this political entity from the perspective of its boundaries and those who crossed them. She begins with a classic debate from the Spanish sixteenth century over the political treatment of mendicants, showing how cosmopolitan ideals of porous boundaries could simultaneously justify the freedoms of itinerant beggars and the activities of European colonists in the Indies. She goes on to examine the boundarie.