In The Laws of Restitution, Robert Stevens shows that there is no unified law of restitution or unjust enrichment. Instead, there are seven or eight different kinds of private law claim, depending on how you count them, which have nothing important in common one with another that have been grouped together by commentators. Few of these claims have anything to do with enrichment, and what is restituted differs between them. Like all private law claims, those gathered here concern (in)justice between individuals, but they have no further unity. Many of them are not based upon an agreement or a wrong, but that negative feature has no utility. "Restitution" or "unjust enrichment' should cease to be discussed as unified areas of law.

With close attention to caselaw and legislation, the work identifies and describes the various reasons for "restitution" that any properly constructed system of private law ought to recognise. It explains how the law of restitution relates to, and is bound up with, contract, torts, equity, and property law.