Joint Winner of the 2001 SPTL Prize for Outstanding Legal Scholarship! In recent years there has been enormous interest in the law of restitution,with many new books and academic articles and a number of important decisions in the courts. However, there remains great controversy and some confusion, partly for historical reasons and partly as a result of continuing differences over the principles underlying the field. There are particular difficulties over the relation of the law of restitution to other areas of law, including contract and property law. In this new and innovative work the author advances a view of the framework of fundamental principles underlying the law of restitution which offers a means of understanding the tangle of conflicting authorities, and then proceeds to examine the case law in light of it. As part of his analysis, the author suggests new approaches to understanding the areas of overlap between restitution, contract, trusts and property law.