This book seeks to analyze the law of restitution, namely that body of law which is concerned with the award of remedies which are assessed by reference to a gain made by a defendant rather than a loss suffered by the claimant. It focuses on those claims which are founded on unjust enrichment, but also considers the award of restitutionary remedies following the commission of a wrong and claims involving the recovery of the claimant's property. The law is analyzed by focusing on the principles which underpin the subject.