This major philosophical work, by one of the world's leading public intellectuals, constructs a new theory of justice, not from abstract ideals or notions of what perfect institutions and rules might be, but from what the results of a system are practically, in the world. It highlights the importance of public reasoning and argues that a system of justice should require the agreement not just of the community which is making laws, but of outsiders who might be affected, or who might have valuable perspectives to offer. The methods and conclusions of the book have implications for many different fields of intellectual activity, not only those connected with justice. It is the most ambitious and wide-ranging book Amartya Sen has yet written.