István Keul has provided a helpful survey of religion and politics in Transylvania during the sixteenth and seventeenth centuries. This book is informed by a thorough engagement with existing studies about Transylvania's religious history in a range of languages as well as by analysis of some printed sources. Keul's book focuses more on the processes of religious reform during the sixteenth century than on religious life during the seventeenth century. He describes the emergence of reform movements during the middle decades of the sixteenth century and the development of Evangelical, Reformed and Unitarian Churches. Keul explains how the Transylvanian diet responded to religious diversity by offering legal rights to a range of ‘received religions’. He also gives coverage to attempts by Catholic princes to promote the interests of their Church during the latter decades of the sixteenth century. In addition, this book devotes significant and welcome space to discussing the state of the Orthodox Church of Transylvania's Romanian-speakers. It reviews the efforts of both Evangelical and Reformed clergy to foster religious reform in Orthodox communities. Keul also provides details about the radical Sabbatarian movement that persisted among some anti-Trinitarian communities despite persecution by the state authorities. For the seventeenth century Keul outlines how Reformed princes supported Calvinist church interests and significantly altered the balance of power between the confessional communities. The book ends with the incorporation of the principality into the Habsburg monarchy in 1691. Transylvania's ‘received religions’ retained their freedoms, although Catholic recovery was steadily promoted by the new Habsburg authorities. In the final chapter Keul assesses the religious history of early modern Transylvania. On the issue of Transylvania's religious diversity, recent studies have emphasised the importance of internal and external political pressures to explain why the diet offered legal rights to a range of religions. However, Keul stresses the contribution of humanist intellectuals in creating a ‘rather tolerant religious atmosphere’ (p. 252) and a ‘liberal religious climate’ (p. 250). Keul also applies the model of confessionalisation to Transylvania. He concludes that it makes little sense to speak of an ‘integrated confessionalism’ in the principality. However, Keul argues that there were ‘self-confessionalising impulses’ within the religious communities in projects to advance social discipline, and suggests that Transylvania experienced a ‘contextual confessionalisation’ (p. 270).