A Theory of Justice by John Rawls is one of the books by which our age will be remembered: perhaps the most important work of moral and political philosophy of the twentieth century, a classic to stand alongside Kant and Mill. Rawls argues that the correct principles of justice are those that would be agreed to by free and rational persons, placed in the 'original position' behind a veil of ignorance: not knowing their own place in society; their class, race, or sex; their abilities, intelligence, or strengths; or even their conception of the good. Accordingly, he derives two principles of justice to regulate the distribution of liberties, and of social and economic goods. In this revised edition the work is presented as Rawls himself wishes it to be transmitted to posterity, with numerous minor revisions and amendments and a new Preface in which Rawls reflects on his presentation of his thesis and explains how and why he has revised it.