The second edition of this textbook lays out the key principles which underlie that body of law known as the law of restitution. This subject was recognised by the House of Lords as a discrete body of law fifteen years ago - although restitutionary principles have, in fact, been evolving for over 200 years. Since the recognition of the subject by the House of Lords the subject has developed dramatically, and even more rapidly since the publication of the first edition of this text in 1999. The law of restitution is concerned with the questions of when restitutionary remedies may be awarded. These are remedies which operate to deprive defendants of gains rather than to compensate claimants for losses. The traditional approach to the subject assumes that restitutionary remedies are only available to reverse unjust enrichment.In this book the author asserts that restitutionary remedies are triggered by three different types of action: The reversal of the defendant's unjust enrichment The commission of a wrong by the defendant The vindication of the claimant's property rights Since the publication of the first edition of this book this model has increasingly been recognised by the courts. In this book the law is examined through analyses of key cases and relevant statutory provisions, demonstrating the way in which the law in used to solve a wide variety of legal problems. The very different views of academics on the nature and ambit of the subject are also carefully considered. The result will be invaluable to students on restitution courses at every level, practitioners and those engaged in research on the subject.