It is typical for theories of contract law to either analyze their subject matter as a mechanism for the enforcement of promises, or to deny the very notion that contract law can be explained as grounded in any unique set of normative principles or sources of moral or legal liability. Liberal theory of contract is traditionally associated with the first of these approaches. This book bucks both these trends by offering a theory of contract law based on a careful philosophical analysis of not only the similarities, but also the much-overlooked differences between contract and promise. Through an examination of a variety of issues pertaining to the nature of promissory and contractual relations and the nature of the institutions that support them, the book presents an intriguing thesis concerning the relations between contract and promise and, consequently, concerning the distinct functions and values which underlie contract law and explain contractual obligation. This thesis is shown to provide not only a firm theoretical basis for explaining the normative underpinnings of contract, but also a promising starting point for dealing with practical issues such as the choice of remedy for breach of contract, and policy issues such as the appropriate scope of the freedom of contract and the role of the state in shaping and regulating contractual activity.