Reformation: Europe's House Divided 1490-1700, by Diarmaid MacCulloch

The keynote of this book is sounded by its lack of a definite article. Previous historians have defined its subject as the European Reformation, a revolt against the medieval western Church that split it permanently into two sorts of Christianity. Professor Diarmaid MacCulloch tells the story of a multiplicity of reform movements in Europe, each determined to improve on the late medieval model, each laying claim to be the true heirs of Christ and his apostles, and all interacting to produce a complicated and unique bundle of religious cultures which between them have reshaped the world. The result is what deserves to become the standard history of early modern Europe religion and its legacy, synthesising and assessing a quarter-century of international scholarship.

This achievement is largely the result of four personal qualities, which between them have made Diarmaid MacCulloch one of the most remarkable professors of the history of the church that Oxford University has seen. The first is the one that he puts in his introduction: that his own current religious position is that of an agnostic or atheist with a background in Anglicanism, which he remembers with affection and respect. This he represents as an advantage in his work as a historian, providing an understanding of Christianity that lacks any confessional bias.

It is possible both to uphold and deny his claim. What shines through this book is not just an instinctual comprehension of western Christianity but an affection and respect for it, tempered by a frank admission of its difficulties and drawbacks. It is not wholly without a confessional tilt, however, because while his treatment of Catholicism and radical Protestantism is both sympathetic and informed, he is most obviously at home with the mainstream, official process of Reformation, his core subject.

This emphasis is a valuable corrective to a natural tendency that has set in among historians with the waning of Christianity in Europe: to show more partiality to the late-medieval Church than to the reformers who destroyed it. This is simply because, to somebody without a Christian faith, the old Church seems to offer far more in the way of artistic and ritual trappings than its critics. To appreciate what Protestantism put in its place, it is more necessary to have some comprehension of the underlying theology.

This pattern relates to MacCulloch's second characteristic as a scholar: he really understands Christian doctrine and is capable of making it seem interesting to outsiders. During the past 20 years historians have increasingly replaced economics with ideas as the driving force behind human development, crediting ideology with a mighty power. In this book the tendency is taken to its logical conclusion, in that theology is seen as the driving force behind all the religious changes of the period.

To MacCulloch, the key factor that made possible the Reformation is nothing to do with the political or social complexion of late-medieval Germany, or the excesses of the Renaissance papacy, but the printing of a scholarly edition of Augustine's works in 1490. The greatest single solvent force on the Church is portrayed not as social, political, or economic, but technological: the invention of printing. It gave European humanity a different sort of way to experience religion - by book-reading - which led directly to a different sort of religion.

The history portrayed here is, then, literally "bookish", and it is notable that the metaphors and similes that spice its pages are drawn overwhelmingly from three worlds: a (high-powered) school, the university system and contemporary information technology. To a great extent, the characters who appear are the sum of what they read and write.

To say that alone, however, would be to rob this work of the humanity with which it invests its characters. Its readers learn that Calvin loathed dancing but enjoyed shove ha'penny, that the unfamiliar comforts of marriage caused Luther massively to acquire fat as well as doctrinal insights, and that Archbishop Laud was a cat-lover who disliked dogs almost as much as he did Puritans.

The third great asset of this historian is that he is fond of churches as well as Churches. The reader is taken on a guided tour of churches in England and Germany, introduced to monuments that reveal the enigmatic nature of late-medieval Christianity, the tenderness of Lutheranism towards images, the evangelical fervour of Elizabethan Puritans. Buildings commonly feature as personalities in their own right.

The fourth asset is an insider's knowledge of the issues that concern modern Protestants and Catholics, which MacCulloch is qualified to relate to historical contexts. If he does not devote much space to the social and political roots of Reformation, he dedicates over a fifth of the book to its impact on society in the short and long term.

Throughout his narrative he has a shrewd and good-natured eye for erotic and homoerotic elements in the make-up of early modern religious leaders. In those dealing with social change, the main focus is on sexuality and its related domains of marriage and the family: precisely the issues that most vex contemporary Churches. In the last analysis, Diarmaid MacCulloch gives readers the stark (and open) choice, that the Bible either has to be accepted or ignored when resolving these issues. That was, of course, the same choice that confronted early-modern people in many other contexts. Like the best of historians, he helps us to understand why we are; and why we need not be so.

Ronald Hutton, professor of history at Bristol University, is author of 'The Triumph of the Moon: a history of modern pagan witchcraft' (OUP)