Classification and Unjust Enrichment

One of the most striking changes in academic research and teaching in recent times has been the appearance of a new subject under the name of restitution or unjust enrichment. This has transformed the treatment of various areas of the common law that were historically neglected, confused and obscure, and has had, over a relatively short period, a marked effect on the approach of some judges to these areas. One of the most influential works has been Peter Birks’s An Introduction to the Law of Restitution, originally published nearly twenty years ago. Much of the literature has been concerned with exploring issues identified by Birks, in the terminology and according to the general approach that he adopted. Birks has been influential not only through this book and the numerous articles and other books that developed and modified his views, but also through scholarship that he has facilitated and promoted: important work has been produced by his research students and by participants in academic seminars and conferences organised by him. In addition, the Restitution Law Review, which Birks helped to found, has provided a new forum for the promotion and discussion of these developments. Given the passage of time and the volume of literature, it is not surprising that Unjust Enrichment reveals some significant changes from the approach originally taken in An Introduction to the Law of Restitution. But the new book is a contribution to the same general project, which is to bring together into a single body of law various claims that were historically separated and unrelated; in other words, to