The rule of law is widely perceived to be a public law doctrine, concerned with the way in which governmental authority conforms to the dictates of law. The goal of this book is to challenge this presumption. The chapters in this volume all consider the idea that the rule of law concerns the nature of law generally and the conditions under which any relationship - that among citizens as well as that between citizens and the state - becomes subject to law. Addressing two major questions, they ask if our understanding of the rule of law is enriched by considering how and to what degree it is expressed or realized in private law, and whether our understanding of the private law is enriched by adding the principles of the rule of law to the traditional list of core private law concepts. Bringing together leading philosophers of private and public law, this volume examines key questions in a little-explored field, and will be essential reading for all those interested in the rule of law and in private law theory.