A comparative examination of remedies for situations commonly referred to as unjustified enrichment in domestic legal systems, reveals a confusing variety of declarations of the highest degree of abstraction and of prescriptions of the most technical kind.1 Statements like: "A person who has been unjustly enriched at the expense of another is required to make restitution to the other,"2 will on account of their generality hardly afford a useful guideline for the everyday decision-maker. Taken as a broad equitable concept, such a principle could be claimed to underlie almost all provisions concerning wealth-transactions in any legal system, whether they be categorized under the headings of "property", "contracts," "trusts" or "torts".3 At such a level of generality, it will have to be regarded as nothing more than an expression of noble sentiments inspiring the creators of the law. Undeniably a large portion of everyday commercial transactions aims at the enrichment of one person at the cost of another, under circumstances which are regarded as perfectly legitimate and within the boundaries of acceptable business risks. At the same time, many if not all domestic legal systems seem to have found it necessary to provide remedies, distinct from the traditional categories and techniques, for certain situations involving accretions of wealth in which corrective relief was considered appropriate. In these cases the enrichment element was so far isolated and identified that it became a distinct and independent motive for judicial action.4 In some legal systems this was done by introducing a general precept of restitution in the case of wealth-transfers considered objectionable. This method required strict and precise arrangements to contain its application to the types of cases in which restitution seemed desirable. Thus the broad provisions of the German Civil Code5 had to be surrounded by a highly elaborate network