Hospitality is a fashionable topic in political and international thought. The most obvious reason for this development is the movement of people across national frontiers to escape persecution or privation in their own countries. The unplanned-for arrival of needy or enterprising strangers is hardly a new phenomenon nor is their disposition to make themselves at home. Yet in recent years immigration and its restriction have come to be seen as a social problem on a global scale — one that raises troubling questions about the duties we, as individuals or societies, have when faced with strangers.