 This article is concerned with social and political equality. In its prescriptive usage, ‘equality’ is a highly contested concept. Its normally positive connotation gives it a rhetorical power suitable for use in political slogans (Westen 1990). At least since the French Revolution, equality has served as one of the leading ideals of the body politic; in this respect, it is at present probably the most controversial of the great social ideals. There is controversy concerning the precise notion of equality, the relation of justice and equality (the principles of equality), the material requirements and measure of the ideal of equality (equality of what?), the extension of equality (equality among whom?), and its status within a comprehensive (liberal) theory of justice (the value of equality). This article will discuss each of these issues in turn.