Probably the best way to understand the nature and purpose for which the authors have written this work is to read their own comments: “The purpose of this book is to provide the reader with Latin texts and English translations of the writings of sixteenth and seventeenth-century Calvinist intellectuals, mainly theologians teaching in academies and universities, concerning that form of politics where most was at stake: warfare” (1). In the introduction, the authors, who are both well-qualified scholars in the field, lay out the structure of the book and provide a treatment of the historiography of Calvinism and warfare which is very helpful in understanding both their purpose in writing and in preparing the reader for what follows. The end of the book includes a beneficial section in which the authors explain their rationale in determining which Reformed authors to include in their volume. Each chapter of Protestant Politics Beyond Calvin includes an informative biographical sketch of the included author which places their work(s) in the context of the objective of the larger volume. The Latin text of each excerpted work is placed on the left facing page, while the English text is on the right, making it very useful for those who have facility in reading Latin.

The book's authors explain why they will use the term Reformed rather than Calvinist to refer to the authors surveyed, namely, in order not to exaggerate Calvin's influence, which they identify as a current practice of Reformation historians. The objective to elicit a position on war from writings of these Reformed theologians, is sought to address a deficiency in the literature as well as to supplement what has been heretofore available primarily from the mainstream reformers, such as Luther, Calvin, and Melanchthon.

The authors identify eleven Reformed theologians/intellectuals, from whose writings they draw material regarding their political philosophy of warfare. Peter Martyr Vermigli, who argued that it was legitimate for Christians to engage in war, but that wars should have a just cause. Lambert Daneau, who, based on his view of the Book of Revelation, believed the kings identified there referred to Protestant kings, and thus saw in it a mandate for holy war against the pope, albeit spiritual, not physical. Bartholomaus Keckerman, who saw as a main purpose of monarchy the maintenance of integrity and tranquility, yet also allowed that subjects could revolt against a prince who dissents from the true religion and rules tyrannically, since even natural law provides for the right to self-defense. Guillaume du Buc, seen as someone who systemized Reformed theology, wrote that subjects could resist a prince when they failed to be protected by the authorities, and identified the role of the lesser magistrate in restraining the destructive impulses of the prince. David Pareus, like Buc, argued that the lesser magistrate had a role to play in restraining the prince's destructive impulses, and that citizens had the right to self-defense when princes acted tyrannically and they were not protected by the authorities.

Johann Heinrich Alsted, whom the authors describe as ambivalent regarding his theory of war, advocated that Christianity should not be advanced by force, presumably by war, while seeing no problem with war against those who deviate from the true worship of God. Amandus Polanus von Polansdorf, also seen by the authors as one who systematized rather than innovated regarding Reformed thought, believed that Christians could declare war to help fellow believers even in other countries, and that victory in any conflict was attributable entirely to God rather than military prowess or strategy. Venceslaus Clemens praised Swedish king Gustavus Adolfus's actions in the Thirty Years’ War as God's instrument waging a holy and just war in defense of Protestantism, since it was His will to help Protestants in their struggle against the Catholics. Dudley Fenner, a Puritan, identified and supported, like several others, the importance of the lesser magistrates in restraining the illicit use of power by kings. Gisbertus Voetius, an influential Dutch theologian, argued that the Dutch Revolt against Spanish rule was a legitimate war since it was waged in defense of the Reformed Church. Finally, Johannes Hoornbeeck, whom the authors credit with making practical application of Dutch Reformed theology, understood war to be justifiable only in the case of self-defense.

In this practical and well-organized work, the authors have made a very significant contribution to Reformation history, and it will likely become a useful reference for students and academics in the field alike.