In his preface, the author expresses concisely the goal of this collection of essays: the 2017 Reformation anniversary will raise the question of what it is that is distinctive about the Reformation. Contrary to an approach that presumed discontinuity, the last several decades saw scholars such as Heiko A. Oberman employ a method that recognises the points of continuity between the late medieval and Reformation eras. Continuing in this academic tradition, Leppin seeks to understand the highly complex developments in scholastic academia, mysticism and humanism that lead up to the processes of the Reformation in terms of gradual change, which, he argues, can best be described by the term ‘transformation’. With this term he intends to include both the elements of continuity and change, but also to keep in view the fact that what is new in the Reformation was not unprecedented, nor an abrupt rupture, but arose out of a gradual development. In twenty-eight articles, of which twenty-four are reprints of articles from the years 1999–2015, Leppin develops and supports this thesis in a manner both varied and lucid. An initial introductory section, composed of three chapters, examines the concept of transformation historiographically in terms of interpretations of the late medieval and Reformation periods over the past hundred years. Ten further articles work out the diversity and the polarities of late medieval piety and theology. Here the author concentrates on highlighting the many points of contact that can be identified in reformatory transformations (for example, in the area of catechetical literature leading up to Luther's Catechism). The third section, specifically on the Reformation, includes another thirteen articles with quite wide-ranging foci. The previously unpublished chapter on sola fide (pp. 333–54), based upon a source-based analysis of the Romans commentary, demonstrates the problematic nature of the perennial debate surrounding Luther's Reformation turn. Two contributions in the final section afford one a small window on the topic of reception. Numerous indices conclude this far-ranging collection, which, as signalled in the preface, provides impressive insight into both the continuities as well as the transformations of the Wittenberg Reformation.