This is a course about Restitution and Unjust enrichment, the body of law concerned with the recovery of gains that a party is not entitled to. It has immense practical value, offering an alternative basis of liability to tort and contract in disputes of various sorts. To give a few examples: a plaintiff may be able to recover in restitution from a defendant on whom benefits have been conferred by mistake; restitution may be available when a benefit is conferred on another in an emergency situation that renders contracting impossible; restitution may also be available when a contract is voided for misrepresentation, duress, or for some other reason consent to the contract is defective; and restitution may be available against defendants who have committed certain wrongs in the eyes of tort law, criminal law, or a statute. The law of restitution raises fundamental questions about the relationship between legal norms and the demands of justice. The course will focus on the law of restitution emphasizing American cases, and will include discussion of the restitutionary remedies that are given in cases of unjust enrichment. Attention will be given throughout to the relationship between the law of restitution and other areas of private law such as contracts, torts, and property.