The Idea of Private Law emerged out of, but went beyond, the great controversies about tort theory that agitated legal scholarship in the last decades of the twentieth century. The origins and aspirations of the book are the subject of this retrospective preface. That tort law became the site of fi erce theoretical contention is not surprising. By its very nature tort law immediately raises an array of pressing theoretical issues. What justifi es the law’s coercive authority to impose obligations on persons who have not assumed them? On what basis does tort law protect certain interests and not others? Where is the line to be drawn between freedom of action and liability for the consequences of action? What is the normative signifi cance of culpability? Can tort law succeed in bringing the arbitrary misfortune of unintended injuries under a rational juridical discipline? In tort law these questions, interesting enough on their own, play themselves out within a subject that has always been fundamental to legal education, so that tort theory resonates broadly within the intellectual culture of academic lawyers.