Originally published in 1978, this book presents a philosophical analysis of the principle of equality, and is also a study of the institutional implications of that principle in the field of social policy. The author distinguishes between a 'procedural' and a 'substantive' version of the principle of equality and considers the implications of both. Procedural equality is identified with the concept of equity and includes the recommendation that like cases should be treated as like. The application of this principle to some political argument in the area of social policy, such as family allowances, is discussed. The author defines the substantive principle as the rule that persons should share the same level of economic welfare. Some difficulties in implementing the equal welfare principle are discussed, with particular application to pensions policy. An original interpretation of the logical relationship between the principle of need and that of equality is proposed, and is applied to the case of the health services. The final 2 chapters deal with the institutional implications of the equality principle. These chapters analyse some major political arguments over the organisation of social policy, such as the compatibility of extensive social welfare measures with a market economy.