Francesco Quatrini's book, which is a revised version of his doctoral dissertation, attends to the life, thought, and impact of Adam Boreel, the seventeenth-century Dutch Collegiant. As early modern historians will know, Collegiants criticized ecclesiastical authority and argued for freedom of conscience, religious toleration, and the separation of church and state. As one of these Collegiants, Quantrini explores Boreel's life and ideas as a way to reevaluate the history of ideas, particularly as Collegiant ideals might function as “early Enlightenment concepts awaiting further development” (15).

In addition to an introduction and conclusion, the book is divided into two parts. The first part is entitled “The Life of Adam Boreel” and acts, primarily, as a biography of Boreel. This section is composed of four chapters that are arranged chronologically and a fifth chapter that is an annotated bibliography of Boreel's work. Throughout these chapters Quatrini pays careful attention to the archival materials in order to reconstruct Boreel's life. Quatrini appropriately challenges previous secondary source works, such as those by Walter Schneider, Leszek Kolakowski, and Ernestine van der Wall, when necessary and admits where source limitations require only tentative conclusions about Boreel's life. Information is sparse on Boreel's early life; regardless, notable conclusions from the first two chapters include Quatrini's argument that Boreel was first in England between 1625 and 1626 (Chapter 1) and the doubt Quatrini casts upon Walther Schneider's suggestion that Boreel was in England in 1632 (Chapter 2). Chapters 3 and 4 are much more thorough given the greater abundance of information on Boreel's life from 1639 to 1654. In Chapter 3 Quatrini helpfully reexamines the role of the founders of the Amsterdam College, and Chapter 4 pays helpfully close attention to Boreel's time in London and his work on both Jesus nazarenus legislator and a Latin translation of the Mishnah.

The fifth chapter, containing Boreel's bibliography, functions somewhat oddly. The book contains a robust bibliography; it would seem logical to include the fifth chapter as a separate section of that bibliography or as a separate appendix. Quatrini does note that the rest of the book will attend to Boreel's thought as based on the writings described in the bibliography, perhaps giving justification for addressing the works in the chapter. However, in this case, the chapter would function more helpfully as the beginning of Part 2.

The second part of the book also contains five chapters and is devoted to the thought of Boreel. Chapter 6 addresses Boreel's arguments against ecclesiastical authority and his plans for a type of universal, united Christian congregation known as the cultum conniventiae. The chapter argues that Boreel believed establishing the cultum conniventiae was the best way to unify Christians and reform Christianity. Chapter 7 expands on the cultum conniventiae as Boreel describes it, demonstrating his idea that the cultum conniventiae would be public meetings where scripture would be read and all members would be able to explain those scripture passages. These congregations would remove preachers and would allow all Christian doctrines and articles to be discussed and, thus, tolerated. Chapter 8 focuses on Boreel's attempts in Jesus Nazarenus legislator to prove the truth of essential Christian doctrines through reason alone, something Boreel believed would unite all Christians. The focus initially shifts in Chapter 9 from Boreel to sources on whom Boreel relied, namely, Sebastian Casetllio, Dirck Coornhert, and Hugo Grotius. The chapter is concerned with the relationship between church and state and argues that Boreel believed the political authorities should not involve themselves in religious issues, focusing, instead, on promoting religious peace and agreement by supporting the cultum conniventiae. The final chapter poses the question of whether Boreel can rightly be called a “mystic.” Quantrini, agreeing with Leszek Kolakowski's work, concludes that Boreel held mystical beliefs much like other early modern dissenters and is not particularly innovative in discussing how to attain mystical union with God.

Quatrini's research is careful and thorough, as evidenced in abundant footnotes and a robust bibliography. Given its uniqueness, Boreel's biography is interesting, and Quatrini's work helpfully provides a more complete picture of Boreel's life, though the nonspecialist may find the details overwhelming. The book's argument is at its best when drawing attention to the ways in which Boreel's life and thought as part of the Collegiant movement provide a more complete understanding of the ways in which religious dissenting groups impacted early Enlightenment concepts. In addition, Quatrini's argument clearly has implications for the study of dissenting religious groups in Europe and, more specifically, the Low Countries. While this is not his main argument, Quatrini's research on Boreel adds to current scholarship in demonstrating that dissident religious groups such as Anabaptists and Arminians were varied and complex. The ways in which Boreel's life forces scholars to reconsider traditional narratives about the Enlightenment, religious toleration, and dissenting religious groups makes Quatrini's work an important contribution for historians interested in a variety of early modern and modern developments. Thus, Adam Boreel (1602–1665): A Collegiant's Attempt to Reform Christianity is a commendable and welcome addition to the field.