The history of religious controversy in Scotland in the late seventeenth and early eighteenth centuries has been revitalised in recent years. Recent work by Alasdair Raffe, Simon Burton and Felicity Loughlin has demonstrated the intellectual and theological intricacies that influenced key figures during the early part of the Scottish Enlightenment. Within these centuries figures such as William Carstares, William Robertson and David Hume are vaunted as making the main contributions to Scottish religious and intellectual thought. This has often meant that lesser-known figures have escaped the lens of historical investigation. Thomas Boston (1676–1732) is one such figure. Although Boston's writings, most notably his Human nature in its fourfold state, have long been regarded as central to the history of Scottish Evangelicalism, Boston's reputation outside of Scotland is not as prominent and his theology has long been overdue a fresh appraisal. Chun Tse's monograph seeks to address this absence and provides a fresh insight into Boston's theology with particular attention to how he interpreted assurance within the Calvinist tradition.

Boston's theology is inextricably connected to the Marrow Controversy that gripped Scotland between 1717 and 1726. This controversy stemmed from the republication in 1718 of The marrow of modern divinity, which was first anonymously published in London in 1645 under the pseudonym of Edward Fisher. Boston himself rediscovered the text in 1700. It had such a profound impact on his theology that in 1717 he recommended it to his colleagues, and the following year the work was republished with a new preface by James Hog of Carnock. The General Assembly of the Church of Scotland, by contrast, believed that the work promoted antinomianism, and in 1720 they prohibited ministers from reading it. Boston himself produced a new edition of the Marrow in 1726, which Tse uses extensively within the book, and the divisions that the text created are widely regarded as contributing to the First Secession in the Church of Scotland in 1733 when Ebenezer Erskine and his colleagues split to form the Associate Presbytery.

The Marrow Controversy is central to Boston's theology, but Tse makes it clear that the controversy is not the only issue when understanding Boston's view of assurance. Rather, as the author convincingly argues, the controversy and Boston's theology of assurance are two sides of the same coin. Both issues influenced Boston, but neither dominated his view of assurance. This is demonstrated in the book's structure which combines intellectual biography with historical theology. After providing some background about the state of scholarship on Boston in the introduction, the first chapter provides an excellent intellectual biography of the minister. Tse clearly demonstrates that Boston, unlike many of his contemporaries, drew most of his theological inspiration from his experience as a minister. Chapter ii provides an investigation into Boston's relationship with the Marrow. Chapter iii then focuses on how Boston interpreted the Trinitarian, Covenantal and Christological dimensions of assurance. A similar approach is taken in chapter iv where Tse examines the soteriological dimension of assurance. Chapter v looks at the ecclesiological and sacramental dimensions of assurance, and the conclusion provides some insightful thoughts on how Boston's view of assurance sits within the theological history of early modern Scotland.

There is much to admire in this study. Tse's analysis of Boston's theology is excellent, and the author should be commended for the level of detail within the book. His analysis of the Marrow, and comprehensive use of all of Boston's published works, has resulted in a study that future scholars of Scottish religion will draw from. Tse demonstrates that Boston drew much of his inspiration from private reading as a parish minister, unlike many of his more famous contemporaries who often both held chairs of divinity and were senior ranking figures within the Church, such as James Hadow at St Andrews. Boston did not have the same level of access to texts and relied heavily on his own private collection and pieces, like the Marrow, that he borrowed from friends. Tse's study demonstrates that Boston was a complex individual whose thought reflected both his own experience and willingness to experiment with ideas that challenged the established Presbyterian orthodoxy within the Church of Scotland.

One of the great strengths of this study is the author's insightful use of Boston's published works to demonstrate how the role of assurance within the Reformed tradition was more complicated within eighteenth-century Scotland. The orthodox Calvinism and Presbyterian government that was re-established within the Church of Scotland in 1690 meant that ministers were expected to adhere to the established interpretations of assurance, grace and salvation that were laid out in the Westminster Confession of Faith. Tse's detailed analysis of Boston's work shows how some ministers interpreted the Church's orthodox Calvinist standards in the Church, but also expanded on it by using texts like the Marrow. All the chapters make extensive use of Boston's works to provide both a comprehensive overview of the minister's thought, and give an insight into the theological complexity of early eighteenth-century Scotland.

Despite the advances that Tse makes in this study, there are areas that could have been improved. Although the monograph makes a significant contribution to the history of early eighteenth-century Scottish religious life, its structure in many ways resembles a doctoral thesis and the author could have expanded the work to address some of the bigger questions in Scottish intellectual life during this formative period. The book is an excellent study of Boston and his theology, but some readers may ask where this fits within the religious origins of the Scottish Enlightenment or the fragmentation of uniformity within the Church of Scotland. Furthermore, it would also have been useful to bring in more works by some of Boston's opponents to demonstrate this bigger picture. Boston's relationship with other figures within the Church of Scotland who represented the orthodox position, like William Hamilton and William Mitchell, for example, would have been helpful. There are parts of the book that read like well-written investigations into Boston's theology, but without more references to the bigger context the significance of this theology is not always clear. Indeed, the structure of these chapters suggest a straightforward adaptation of the thesis rather than an expansion of it.

Overall, this is a comprehensive study that has provided a long overdue investigation into such an important figure within the Scottish Presbyterian intellectual tradition. Tse has set a benchmark for future investigations into the historical theology of early modern Scotland and, although parts of the book could have been expanded upon more, this study will be the basis for future investigations into Boston.