This book continues and revises the ideas of justice as fairness that John Rawls presented in A Theory of Justice but changes its philosophical interpretation in a fundamental way. That previous work assumed what Rawls calls a "well-ordered society," one that is stable and relatively homogenous in its basic moral beliefs and in which there is broad agreement about what constitutes the good life. This book goes deeper to ask how a stable and just society of free and equal citizens can live in concord when divided by reasonable but incompatible doctrines.