While the modern world is divided into roughly 200 sovereign states, many of the problems we are experiencing are global in scale and cannot be solved by nation states acting alone. The one world has many different traditions, too: very different ideas exist about how a nation state should be organised politically, the universality of human rights, relations between women and men - indeed, about everything of any importance. Different developments in our world pose a challenge to legal and social philosophers. What can we say about justice in a pluralist world? Is there some universal justice? Are there universal human rights? What is the function of the state in the modern world? How should the law deal with global problems, such as the environment or migration? And how can we or should we argue about such issues? Such are the problems dealt with by the 20th world congress of the International Association for Philosophy of Law and Social Philosophy, held in Amsterdam in June 2001 and published in this book, which can be read with pleasure and profit by legal and social philosophers, students of human rights, political philosophers and all those who want to know about the challenge