In Anglo-American academic political philosophy, the publication of John Rawls's A Theory of Justice in 1971 is considered a milestone. Rawls used a thought experiment, the original position, in which representative parties choose principles of justice for the basic structure of society from behind a veil of ignorance. Rawls also offered a criticism of utilitarian approaches to questions of political justice. Robert Nozick's 1974 book Anarchy, State, and Utopia, which won a National Book Award, responded to Rawls from a libertarian perspective and gained academic respectability for libertarian viewpoints.