Rawls' best-known work was the 1971 book "A Theory of Justice," which revived the idea of the social compact. Each person, Rawls argued, is entitled to certain rights that cannot be overridden even in the interests of society as a whole.
Born in Baltimore, Rawls received his undergraduate and graduate degrees from Princeton University. He joined Harvard's philosophy department in 1962 and was given the title of university professor, Harvard's highest teaching post, in 1979.
His other works included "Political Liberalism" (1993) and "Justice as Fairness: A Restatement" (2001).