This book grew out of a variety of courses and seminars I have taught at Cornell University since 1964. These have been exciting times for legal philosophy – sparked by social crises and intellectual adventures. That period is far from over.

And so this book is not a text for a static subject, but a report in progress. It is meant, first of all, for those who wish to become acquainted with contemporary reflections on the nature of law and, especially, its relations to moral reasoning. In that respect it is meant to serve as an introduction to legal philosophy. But it may also interest those who, from the perspective of a single discipline such as law, philosophy, or political science, already have some knowledge of the subject and wish to explore it further, systematically.

I am grateful to Jeremy Mynott of the Cambridge University Press for first suggesting this project to me, and for his patience thereafter. For thoughtful, helpful comments on the draft, I am indebted to Neil MacCormick, William Nelson, and – most especially – David Brink. Judy Oltz and Jylanda Diles produced impeccable typescripts with cheerful efficiency. The Cornell Law School and the Sage School of Philosophy provided time, support, and stimulation.

The book is partial (if symbolic) payment of a debt to those who have most helped me learn about the subject – those who have given me the opportunity to help them learn about it.