RETHINKING UNJUST ENRICHMENT: HISTORY, SOCIOLOGY, DOCTRINE AND THEORY. Edited by Warren Swain, Professor of Law, University of Auckland, and Sagi Peari, Associate Professor, University of Western Australia Law School. Oxford University Press, Oxford (2023) xxviii and 354 pp + 12 pp Index. Hardback £110.

This book purports to present a challenge to the orthodox Law of Unjust Enrichment by sceptics who, the editors conclude, have “provided a joint manifesto” about the future of the law and who seek constructive dialogue with supporters of the subject to respond to the identified concerns. As somebody who has defended the recognition of the Law of Unjust Enrichment, within the wider field of the Law of Restitution, I imagine that I am cast in the role of supporter, albeit that I have long been sceptical about the perceived breadth of unjust enrichment (as advocated by other “supporters”), especially in the proprietary context, and I have welcomed much of the recent refinement and narrowing of unjust enrichment in England through judicial developments. But, whatever our perspective, it is important that there should be constructive engagement with the disparate views about unjust enrichment and I welcome all contributions which reflect on the function of and justification for this body of law, especially if they construct workable alternatives. This collection of 16 essays, which derive from three online symposia which took place in September 2022, does provide much food for thought about the nature of unjust enrichment in various jurisdictions, but no “joint manifesto” emerges and, in fact, a significant number of the contributions cannot be characterised as sceptical, but assume the legitimacy of unjust enrichment and then provide thoughtful analysis of its operation: consistent with continued evolution rather than revolution.

The book is divided into four parts, reflecting the themes of History, Sociology, Theory and Doctrine. Two of the chapters in the History section provide a helpful description and analysis of the evolution of unjust enrichment in China and India. Siyi Lin examines the transplantation of unjust enrichment into China from Germany in particular, whereas Arpita Gupta considers its development in India, where it benefited from early codification under the Indian Contracts Act. Unjust enrichment jurisprudence has focused too much on the Western legal tradition, and, whilst unjust enrichment in China and India has been influenced by that tradition, the subsequent developments in both jurisdictions are important in their own right as significant global players but also because they shed light on the context of claims and interpretations of the law in the West. Both authors consider unjust enrichment in these countries to be wanting and, in doing so, both rely on the Birksian template of unjust enrichment to critique the law: hardly the contributions of unjust enrichment sceptics.