 If the right-libertarian celebrates individual property rights, the left-libertarian regards property rights as a collective phenomenon. Left-libertarian thought is complex, and merits its own examination; we will not provide an adequate analysis of that thought here. We mean, instead, to note that one particular left-libertarian idea—that individual property rights in natural resources and in territory must acknowledge the symmetrical claims of all human persons to the use of those goods—has proven to be a fruitful one in theorizing about global distributive justice.