“Didn't you read the fine print?” This frequent caption in humorous cartoons is a reminder of the pervasiveness of contracts in modern life and their often inscrutable character. Warren Swain's “unashamedly doctrinal” (5) account of English contract law may also appear impenetrable to some. The Law of Contract 1670–1870 is explicitly not intended as a comprehensive analysis of contract law during this period of British commercial ascendency. Instead, Swain investigates contract law “through some key themes,” (8) including the dynamics of legal change, the impact of legal writing on the development of doctrine, and the role of public policy in judicial decision making. Adopting a formalist approach that privileges dynamics within the law as agents of change, Swain suggests an alternative interpretation of the development of contract law in England.

By doing so, the book engages with two large bodies of secondary literature, neither of which is laid out very clearly for the nonspecialist. The first reconstructs the development of English contract law in this period. Put briefly, beginning in the sixteenth century the common law courts increasingly began to hear business that otherwise had been resolved in mercantile courts, a shift that accelerated throughout the seventeenth and eighteenth centuries. These cases often involved juries of merchants applying recognized commercial customs from outside the common law. Since merchants tended to favor certainty in the law, pressure grew for the common law judges to clarify the rules governing commercial disputes and to reconcile them with older common law ideas about contract. The pivotal figure in these reforms is usually identified as William Murray, Lord Mansfield (1705–1793). But a unified theory of contract, the classical model of contract, only emerged after 1800 to explain how very different contracts shared underlying principles. The lawyers of the day, finding little in the way of earlier theoretical reflection within the common law to guide their work, borrowed from sources as diverse as the civil law and the earlier French jurist Robert Joseph Pothier (1699–1772).

Swain's contribution to this narrative is one of adjustment rather than displacement, and some of his research has appeared in his earlier publications. He argues that changes in contract law reflected a long-term evolution that built steadily, if at times fitfully, as the judges integrated commercial custom with common law. This argument for continuity contrasts with Morton Horwitz's much-debated claim that between c. 1770–1820 commercial interests fundamentally transformed Anglo-American contract law into a form that was more suited to a ruthless market economy. Swain engages this second body of literature by making clear his rejection of Horwitz's thesis and its emphasis on discontinuity.

Swain opens the book with a place-setting discussion of the early modern law of contract and its relationship to the medieval forms of action. Subsequent chapters on lawyers and merchants describe the absorption of mercantile custom into the common law and the contribution of juries of merchants to this development. In the next three chapters Swain examines equity and Lord Mansfield's and his successors' impact on contract law. Swain follows these chapters are followed by an investigation into the development of the classical model of contract that untangles some of the extramural legal influences on the formulation of contract theory, especially the impact of Pothier. In the final chapters Swain illustrates the role of public policy in judicial decision making, usury and the Chancery, and contract law and statute. Throughout, Swain presents a gradualist model of legal change that explicitly avoids generalizations. His conclusions are therefore nuanced or vague, depending on one's point of view. For example, summarizing the impact of legal writers on the development of the law, a major theme of the book, Swain observes that these writers were sometimes influential and sometimes not (177), but they were most influential from 1850 to 1900 (228).

This is a history of the law from within the law. Insightful connections between the law and social change are few. Swain's analysis of context also tends to the superficial: the Enlightenment was “undoubtedly a time during which ideas were becoming more important” (275). At points these problems also undermine the text's explanatory strength. Although one of the crucial drivers of legal change in contract was the migration of litigation from mercantile courts, which Swain largely identifies with the Admiralty, he provides no substantial explanation for this phenomenon. The discussion of wagering contracts reveals the shortcomings of such inattention to external details, as when Swain paraphrases a wager about the “Isle of White” (234), or the Isle of Wight in the original source. More problematically Swain goes on to confuse the identities of the plaintiff and defendant in the discussion of Hayes v. Jacques (1777), a case that must be reconstructed from newspaper sources. This problem muddles the subsequent analysis.

The light treatment of the social context may, in fairness, reflect the formalist method employed throughout. But there are issues here too. For example, the analysis of cases related to wagering contacts is intended to demonstrate that there was no “overarching public policy doctrine” (245) in judicial decision making during the eighteenth-century. Though it is unclear what this means, an analysis of this class of cases seems too narrow to support such a general assertion. This concern is reinforced when Swain later observes in a discussion of restraint of trade that “Until the 1830s, judges were quite comfortable with emphasising public policy” (247).

Swain has, nonetheless, amassed a remarkable amount of material drawn from cases, including manuscript reports, and legal treatises about a complex and vital branch of the law. His book presents a provocative corrective to more abrupt accounts of legal change, and his recognition that most early modern lawyers saw the functioning of law though the lens of practice rather than theory is important. But while readers other than those with a specialized interest in contract law, may not, as Swain warns, judge the book “excruciatingly tedious,” (5) this is a study written for those who enjoy reading the fine print.