The subject matter of Zachary Purvis's dissertation is narrower than its title suggests. The book treats the ‘theological encyclopedia’, a literary genre that emerged during the middle of the eighteenth century, as a kind of synoptic introduction or guidebook to theology as a system of knowledge, as a pedagogical project, ecclesiastical and pastoral practice, and a body of literature. In its function as a practical guide, the theological encyclopedia represented part of a larger genre that sought to systematise the knowledge represented by the several faculties at central European universities. Purvis describes the broader genre as a ‘remarkably broad and dynamic phenomenon’, a motor that drove ‘many of the structural transformations’ in German universities (p. 5). In the case of theology, the encyclopedia synthesised theological reflection with the institutional requirements of the university to establish Protestant theology as a scientific discipline (Wissenschaft). This story has been told before, among others by the American scholars Edward Farley and Thomas Albert Howard, Leonhard Hell (a German Catholic) and Johannes Zachhuber, Purvis's Doktorvater. The service of Purvis's dissertation lies foremost in exploiting archival sources to provide a great deal more detail to the story during the pivotal era between 1750 and 1850.

During its gestation in the eighteenth century, above all at the universities of Halle and Göttingen, the controlling metaphor in the theological encyclopedia was the map; its function was to chart the interconnections among all branches of theological knowledge and practice – exegesis, history, dogmatics and practical theology. Even as they standardised courses of study in the theological faculties, early encyclopedias served important pedagogical ends as introductory textbooks. However, both the institutional and philosophical underpinnings of the theological encyclopedia altered in the wake of revolutionary changes that came to central Europe at the beginning of the nineteenth century. In the light of post-Kantian idealism and historicism, the genre underwent, as Purvis writes, a ‘dramatic recasting’ (p. 80); it no longer served only as a tool to organise knowledge, but now also embodied a ‘theological-philosophical system in its own right’ (p. 79). The guiding principle was to be the organic unity of all knowledge. The theological encyclopedia thus became the charter of a Wissenschaft, a ‘comprehensive, “living” apparatus of theology’, which was, like the other emergent academic disciplines, itself henceforth understood as a ‘new, rigorous, critical and historical science’ (p. 80). The great exponent of this new understanding, as well as the author in 1811 of one of the most influential theological encyclopedias, was Friedrich Schleiermacher. Schleiermacher's achievement was to wed theology to the modern precepts of academic scholarship by tying dogmatics to historical criticism. In a way that anticipated the work of Adolf Harnack, he insisted that the ideal, essential tenets of Christianity were accessible to historical analysis properly trained.

The remainder of Purvis's volume analyses the fortunes of Schleiermacher's project to reconcile scholarship and revelation in the practical service of Protestant Christianity. One challenge came from post-Kantian philosophy itself, particularly from Schleiermacher's colleagues at the University of Berlin. J. G. Fichte, who dismissed revelation and the supernatural as legitimate objects of scholarship, wished to reduce academic theology to the history of religions. Hegel and his followers then attacked Schleiermacher's historical approach to Christian dogma, advocating instead a speculative theology in which God revealed himself in history as the Spirit (Geist). Hegel's student David Friedrich Strauss argued that the consequence of Schleiermacher's critical historical analysis would be to subvert dogmatic claims of all kinds. The most effective defence of Schleiermacher's vision of theology as an academic discipline came from Karl Rudolf Hagenbach, whose Encyklopädie und Methodologie der theologischen Wissenschaften (1833) represented the most successful and influential theological encyclopedia of the modern era. In it Hagenbach formulated the bases of a ‘mediating theology’ (Vermittlungstheologie), which, in marrying the exegesis of biblical texts with historical source-criticism, offered German Protestants an immensely appealing synthesis of faith and scholarship, belief and historical criticism.

The account ends on this happy note, well before the First World War destroyed the foundations of the Kulturprotestantismus that issued from the synthesis. In several respects, however, Purvis's study understates the complexity of the subject. The author appears to treat the theological encyclopedia less as a product and register of developments in academic theology than as an agent, a ‘juggernaut force’ (p. 5) in the progressive developments that he describes in the German universities. This claim is difficult to demonstrate, and it runs the risk of privileging form over substance. Above all, it tends to underplay the fact that German Protestant theology had to respond to forces that lay well outside the theological faculties. The theological encyclopedias contended with pressures that receive but brief mention in this volume, such as the mobilisation of popular piety and deprecation of rationalism, as well as the fact – dramatically emphasised in the Prussian Protestant Union – that princely power extended well beyond questions of governance into issues of liturgy and doctrine. The role of the theological encyclopedia in the contemporary development of central European Catholicism would have rewarded more attention than it receives here, for the tensions among ecclesiastical authority, revelation, dogma and historical criticism were of a different, more troublesome order. Finally, even within the Protestant faculties the Verwissenschaftlichung of theology was neither unproblematic nor unopposed, as Thomas Albert Howard's book has recently emphasised. The early criticism from Fichte and Strauss resonated to doubts that theology should or could be an academic discipline like history, economics or chemistry.

Finally, although its subject matter is the organisation of knowledge, this is not a well organised book. Its paragraph structure is weak. Long excursive passages not only interrupt the logical progression of paragraphs but also invade the paragraphs themselves to complicate the reader's quest for narrative coherence. More careful editing would doubtless have made the prose less an obstacle to the success of the book's challenging argument.