The apparent paradox in the subtitle of this history of Christianity – ‘The First Three Thousand Years’ – is explained on page 56: the Christian religion has a background in Hebrew and Greek thought and practice, and so the added thousand years may be seen as ‘effectively the first millennium of Christian history’. This new study, the author tells us, is ‘not a work of primary-source research’ but a synthesis of books conveying ‘the current state of historical scholarship across the world’. The range of this reading is not quite as wide as it looks, however, and scarcely sustains the claim that this book is different from ‘any of its predecessors’ precisely because it looks into Christian origins. Diarmaid MacCulloch’s presentation is nevertheless extremely impressive – the fruit, as he explains at the start, of ‘an extended period of unpaid leave’ and the accompanying allure of a forthcoming television series. This last signifies that the ideas he promotes will have a hugely greater currency than is normal with works of religious history, and are likely to become, at least for a time, a kind of orthodoxy.