Among political philosophers, discussion of Charles Beitz's very important book Political Theory and International Relations has focused mainly on Part Three, in which Beitz addresses the issue of global distributive justice, and argues in favour of applying Rawls's difference principle globally: an ideally just world would be one in which the share of income and other primary goods going to the least advantaged group of persons would be maximised, no matter which society those persons belonged to. There has been much debate about whether relationships across the world are cooperative in the sense that this principle is thought to presuppose, how one might construct an international index of advantage and disadvantage, and so forth. Beitz himself has contributed to this debate, and it remains central to contemporary work on global justice.