Noting the multi-confessional Dutch society, Kooi describes the “interconfessional conviviality” (4) of Catholics and Calvinists as they operated together in a pluriform society. Confessional coexistence forged a unique living experience during the late sixteenth and seventeenth centuries. Kooi studies this by outlining how the Catholics and Reformed interacted in three distinct arenas: confessional space, civic space, and private space (11–12).

In chapter 1, Kooi identifies the historical context that birthed the heterogeneous landscape. The Netherlands, revolting against Catholic Spain, became the new Dutch Republic under William of Orange. The political upheaval fueled religious antagonism, bringing both the disestablishment of the Catholic church in the 1570s and the creation of a Reformed state church. Uniquely, however, the new Dutch Republic was committed to private freedom of conscience yet formally allowed only one official church—the Reformed. The Catholic contingency was therefore in one sense illegal but in another allowed. Kooi summarizes this well: one could “profess Catholicism” personally but not “practice it” publically (31).

Chapter 2 explains the interaction that occurred in confessional space, especially during the high points of confessional development throughout 1620–1660. The Catholic contingent, despite “technical illegality” (53), was organized as the Holland Mission. Services were private, and altars were portable. During this time, Reformed opposition continued, but it was really limited to the realm of rhetoric, such as the printing of pamphlets and placards. Confessions were used for not simply condemning but distinguishing and demarcating between groups (109).

The local magistrates maintained public peace in the civic space, which Kooi handles in chapter 3. Officially, and nationally, Catholicism was outlawed; yet, locally it was tolerated—though, likely this term is too optimistic and problematic to be used, at least in the sense it is understood today (22, 92). Across the six major cities this was on a continuum, with Amsterdam and Haarlem being the most lenient and Dordrecht being the least accommodating. The latter, as Kooi notes, is not surprising given the city's penchant for Reformed orthodoxy (117). Kooi demonstrates how the “machinery” that allowed Catholic existence developed quickly (103). Recognition money made “invisibility [for Catholics] in civic space possible through official connivance” (105). Though wrestling through turmoil for decades, by 1660 Catholics and Calvinists were in a state of relatively peaceful coexistence (125).

Confessional adherents from either side were able to traverse what was at best only a semi-permeable dividing line. This is surveyed in chapter 4, where Kooi details conversion accounts and statistics from both the Catholic and Reformed perspectives. Missionary activity was the lifeblood of the Catholic Holland Mission—“by definition a proselytizing body” (153). The klopjes, women who lived communally but did not take vows—perhaps numbering five thousand strong by the end of the seventeenth century—were instrumental in advancing the Catholic cause. The Reformed occupied themselves as well with evangelistic endeavors, such as the publication of tracts and sermons. In general, conversion was limited to the laypeople, though even several clergy converted (or, apostatized, depending on the perspective).

Chapter 5 focuses on interconfessional family life. Intra-spousal relationships, particularly, were often bombarded by outside ecclesiastical forces; however, within the home, “kinship could and often did trump religion” (191). Parent-child relationships, especially when both spouses were of differing confessional subscriptions, did cause unique difficulties—baptism likely was the most emotionally charged of these (204). Schooling was also a dilemma.

Kooi demonstrates well how the tempestuous waters surrounding the Catholics and Calvinists were actually conducive to greater religious pluriformity. As she notes in her conclusion, diversity fueled toleration; and toleration in turn created greater diversity (220). This was especially true in the practical lives of the laypeople. While lines were sharp between the Reformed and Catholic churches, they often blurred significantly in daily interactions among the public.

Kooi displays a thesis well researched in primary sources, especially little-known records of specific cases and examples. Her writing and argumentation is smooth and convincing. There are, however, three points that could be sharpened or improved. First, Kooi seems to be weighted on the Catholic side. Perhaps this is because the Catholics were always working offensively to survive, thus meriting greater attention. However, the Reformed contingent needs to be detailed more, especially in the late sixteenth century as Catholic Spain was thrown off and the Reformed really began to expand. Thus, a bit more evenness is required in order to understand how Catholics and Calvinists coexisted in the Netherlands. Second, along this line, one significant weakness is Kooi's largely ignoring the strength of Reformed confessionalism. One lengthy paragraph alone analyzes the Synod of Dordrecht. The instillation of the Three Forms of Unity into the Dutch Reformed church and how this worked out practically in ecclesiastical and private life is bypassed entirely. These factors are necessary for a greater understanding of the confessional interaction of both groups. Third, though Kooi is to be commended for her demonstration of coexistence among the common people, she does not have sufficient material detailing the interaction of the leadership dealing with both Catholics and Calvinists in this period. Her thorough treatment of the general public needs to be replicated in her outlining of public officials, particularly at the local level where sharing space actually occurred.

Notwithstanding these constructive criticisms, this work is a major achievement that breaks new ground and sheds much new light on the interconfessional conviviality of Catholics and Calvinists as they operated together in a pluriform society.