What is a just political order? What does justice require of us? These are perennial questions of political philosophy. John Rawls, generally acknowledged to be one of the most influential political philosophers of the twentieth century, answered them in a way that has drawn widespread attention, not only from political philosophers, but from political scientists, economists, those in the field of public policy, and experts in jurisprudence. It is not only academics who have been inspired by Rawls’ ideas; they have also influenced the theory of government and continue to play a role in actual public political debates. This introduction outlines Rawls’ work on the theory of justice. Focusing on Rawls’ own writings, from his first publication in 1951 to his final ones some fifty years later, Percy B. Lehning demonstrates how and why they can be considered as one consistent and coherent body of work.