This new textbook outlines the general principles of the rapidly developing subject of the Law of Restitution. Restitution is concerned with the reversing of unjust enrichment and was recently recognized as a discrete body of law by the House of Lords although restitutionary principles have in fact been evolving for over 200 years. Rather than taking the traditional approach which assumes that restitutionary remedies will be awarded against a defendant only where it can be shown that the defendant has been unjustly enriched at the expense of the plaintiff.The book asserts that the law of restitution is simply concerned with the question of when restitutionary remedies may be awarded, that is remedies which are assessed by reference to a benefit obtained by the defendant. But in determining whether restitutionary remedies are available it is necessary to identify the causes of the action which triggers them. There are three such causes of action, namely the reversal of the defendants unjust enrichment, the commission of a wrong by the defendant, and the vindication of the defendants property rights. The state of the law is examined through analyses of the statutory provisions and key cases demonstrating the way the law is used to resolve a wide variety of legal problems. The very different views of academics as to the nature and ambit of the subject are also identified. This book will be invaluable to students on restitution courses at every level.