Part I of this book, “The Doctrinal Canon”, consists of 18 essays exploring fiduciary principles arising within specified fields of law. The aim is “to explain when fiduciary principles arise and how they govern specific relationships” (p. xxi). The essays cover fact-based fiduciary relationships (by Daniel Kelly), agency law (by Deborah DeMott), trust law (by Robert Sitkoff), corporate law (by Julian Velasco), unincorporated entity law (by Mohsen Manesh), charity and non-profit law (by Lloyd Hitoshi Mayer), banking law (by Andrew Tuch), the law governing investment advice (by Arthur Laby), pension law (by Dana Muir), employment law (by Aditi Bagchi), bankruptcy and insolvency law (by John Pottow), family law (by Elizabeth Scott and Ben Chen), the law governing surrogate decision-making (by Nina Kohn), the law regulating lawyers’ representation of clients (by Richard Painter), health-care law (by Mark Hall), the law governing public offices (by Ethan Leib and Stephen Galoob), the application of fiduciary principles to the state, for example in administrative and constitutional law (by D. Theodore Rave), and international law (by Evan Criddle).

Part II, “A Conceptual Synthesis”, contains six essays, each examining an over-arching aspect of fiduciary law. The goal is to offer a “synthetic analysis of conceptual patterns that hold across the fiduciary doctrinal canon” (p. xxiii). The essays explore the identification of fiduciary relationships (by Paul Miller), the duty of loyalty (by Andrew Gold), the duty of care (by John Goldberg), other fiduciary duties, which are described as “implementing loyalty and care” (by Robert Sitkoff), mandatory and default rules in fiduciary law (by Daniel Clarry), and fiduciary remedies (by Samuel Bray).

Part III, “Fiduciary Law Across History and Legal Systems”, comprises 10 essays, each contributing to the understanding of fiduciary principles in historical or comparative perspective. The purpose is to “show how different legal systems have embraced and extended fiduciary principles in their own unique ways over time” (p. xxv). The essays cover English common law (by Joshua Getzler), canon law (by Richard Helmholz), Roman law (by David Johnston), classical Islamic law (by Mohammad Fadel), classical Jewish law (by Chaim Saiman), contemporary common-law systems (by Matthew Conaglen), European civil-law systems (by Martin Gelter and Geneviève Helleringer), Chinese law (by Nicholas Howson, on corporate and partnership law), Indian law (by Vikramaditya Khanna), and Japanese law (by J. Mark Ramsayer and Masayuki Tamaruya, primarily on corporate law but with some discussion of non-profits, guardians and investment advisers and managers).

Part IV, “The Future of Fiduciary Law and Theory”, contains 14 essays. Four of the essays offer interdisciplinary perspectives on fiduciary law, using insights from economics (by Richard Brooks), philosophy (by Charlie Webb), psychology (by Tess Wilkinson-Ryan), and empirical analysis (by Jonathan Klick and Max Schanzenbach, emphasising studies on corporate governance, fiduciary investment and the provision of health care). Six of the essays provide broad perspectives on fiduciary law and its relationship to equity (by Henry Smith), good faith and publicness (by Hillary Sale, focusing on corporate law but also providing a discussion of good faith in trust law), moral norms (by James Penner), social norms (by Matthew Harding), corruption (by Sung Hui Kim), and pluralism (by Hanoch Dagan). Two of the essays examine “the development of fiduciary principles in specific regulatory contexts” (p. xxviii): financial regulation (by Howell Jackson and Talia Gillis) and Delaware corporate law (by Lawrence Hammermesh and Leo Strine Jr.). The final two essays “look beyond the current state of fiduciary law and theory and identify promising areas for further doctrinal development and scholarly research” (p. xxviii) in private fiduciary law (by Paul Miller) and public fiduciary law (by Evan Fox-Decent).

The book has “four principal objectives” (p. ix). The first is to offer “an accessible synthesis of fiduciary law across the many contexts in which fiduciary principles arise” (p. ix). The second is to provide “a standard reference for understanding the content, nature, function, and structure of fiduciary principles” (p. ix). The third is to demonstrate “that fiduciary law may be understood as a coherent field unto itself, confirming the importance of a research agenda in fiduciary law, as compared to piecemeal study of fiduciary principles in different fields” (p. ix). The fourth is to provide “new historical, comparative, and interdisciplinary perspectives on fiduciary law” (p. ix).

With respect to the first, second and fourth of these goals, the book's success is evident. The quality of the essays and the breadth of the topics render the book an indispensable reference and an essential and accessible starting point for study and research. The inclusion of interdisciplinary, comparative and historical perspectives is especially to be applauded, though with respect to comparative essays the editors might have encouraged more discussion of trust law – and invited a few more contributors from non-Anglophone nations.

Does the book succeed in its third goal, to demonstrate that “fiduciary law may be understood as a coherent field unto itself … as compared to the piecemeal study of fiduciary principles in different fields” (p. ix)? Dagan's thoughtful essay bears importantly on this question, offering an understanding of fiduciary law as a “plural legal category” (p. 849) – a category that, at a minimum, is a useful “category for thinking” if not necessarily a “category for deciding” (p. 836). Still, the evidence is mixed. Field-specific distinctions remain significant, such as between the duty of loyalty in trust law (“sole interest”) and corporate law (“best interest”). Another distinction, unmentioned but perhaps specific to the field of donative transfers, is the use of the constructive trust to remedy not only “fraud” or “exploit[ation]” (p. 455) but also the donor's unilateral mistake (see Restatement Third of Property: Wills and Other Donative Transfers §4.1 cmt f. (1999)). The role of good faith also raises challenges. Is there a fiduciary duty of good faith – or in Penner's formulation, drawing on Conaglen (see p. 571), a fiduciary duty “not to act in bad faith” (p. 786)? Different essays take different approaches to this question (compare p. 778 with p. 420, n. 3). Last but not least, it is worth noting that even some of the book's contributors have elsewhere criticised what might be called the over-application of fiduciary concepts (see S. Bray and P. Miller, “Against Fiduciary Constitutionalism” (2020) 106 Va.L.Rev., forthcoming, available on SSRN).

Nevertheless, the caveats are minor compared with what has been achieved. The book is an impressive addition to this Oxford series. The book is an instant classic and will be the standard reference. The editors and contributors are to be commended.