"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.