This paper is not about equality. It is about egalitarianism and about principles of equality. I shall not discuss or question the sense in which men are or should be equal. Nor will I query any claims that men are or should be equal in some respects or others. I shall, however, try to explain the sense in which a political morality can be said to be egalitarian and to unravel the presuppositions of egalitarianism.