Theories of social justice are necessarily abstract, reaching beyond the particular and the immediate to the general and the timeless. Yet such theories, addressing the world and its problems, must respond to the real and changing dilemmas of the day. A brilliant work of practical philosophy, Frontiers of Justice is dedicated to this proposition. Taking up three urgent problems of social justice neglected by current theories and thus harder to tackle in practical terms and everyday life, Martha Nussbaum seeks a theory of social justice that can guide us to a richer, more responsive approach to social co-operation. The idea of the social contract - especially as developed in the work of John Rawls - is one of the most powerful approaches to social justice in the Western tradition. But as Nussbaum demonstrates, even Rawls's theory, suggesting a contract for mutual advantage among approximate equals, cannot address questions of social justice posed by unequal parties. How, for instance, can we extend the equal rights of citizenship - education, health care, political rights and liberties - to those with physical and mental disabilities? How can we extend justice and dignified life conditions to all citizens of the world? And how, finally, can we bring our treatment of non-human animals into our notions of social justice? Exploring the limitations of the social contract in these three areas, Nussbaum devises an alternative theory based on the idea of 'capabilities.' She helps us to think more clearly about the purposes of political co-operation and the nature of political principles - and to look to a future of greater justice for all.