This book contains the historically most important discussions of the philosophical foundations of left-libertarianism. Like the more familiar right-libertarianism (such as that of Nozick), left-libertarianism holds that agents own themselves (and thus owe no service the others expect as the result of voluntary action). Unlike right-libertarianism, however, left-libertarianism holds that natural resources are owned by the members of society in some egalitarian manner, and may be appropriated only with their permission, or with a significant payment to them.