Rawls’s monumental A Theory of Justice is very likely the most important work of political philosophy of the last hundred years. It’s often said that all political philosophy published after A Theory of Justice came out in 1971 is, in one way or another, a reaction to it. The theory Rawls lays out isn’t a direct attack on libertarianism—some have even argued it can be interpreted as a powerful foundation for a libertarian society. But it forms much of the background for all contemporary debate, especially within the liberal tradition, making it crucial that any student of libertarian thought understand Rawls.