G.'s intention for this volume is ‘to gather into a single accessible collection the sources that illustrate this crucial period’ (p. viii), and he appears to have succeeded in this aim. The index of authors shows a huge and wide-ranging selection of sources, and includes pagan, Christian and legal literature. These are not confined to the Graeco-Roman world, but G. also takes into account texts such as The Life of Columba, The Armenian History and a Turfan fragment, which show the complexity and range of the topic. Although the focus is more towards the western, Latin branch of Christianity, there is a good balance throughout between the various sources to give a detailed representation of the topic. In addition, the volume includes: a chronological table which places the sources in context amongst the reigns of the emperors as well as some more notable historical events; two maps, one depicting the Empire under Constantine, the other Europe in a.d. 500; and a selection of further reading following each chapter. All the sources have been translated, which adds to the accessibility of the book.

The volume consists of twenty chapters, which can be sectioned into five broad themes: Christianity up to and including Constantine, Christian doctrine and the schisms, Organisation within the Church, the Christianisation of the existing Graeco-Roman framework, and the concept of relics and missionaries. Thus the book covers a timescale from the late-third through to the early-eighth century with an epilogue reaching ‘The Dawn of Medieval Christendom’. Each chapter has a broad chronological framework through which G. weaves together the sources with the explanatory narrative in such a way that makes the text enjoyable to read. This approach shows clearly not only the significance of the sources but also how they influenced each other, and how events unfolded.

A heavily emphasised theme is that ‘the fourth century witnessed the transformation of Christianity into the dominant faith of the Later Roman empire’ (p. 65) and that this century saw the transformation of the Christian faith. This is commented on in most chapters and feels repetitive when reading through the whole volume rather than dipping into individual chapters. A fascinating inclusion is the short section in Chapter 7, ‘Scripture and Liturgy’, which considers the development of hymns and how they became established in Christian worship (pp. 90–2). G. notes that ‘the development of the liturgy made music and hymn-singing an important part of worship’ (p. 90) and that it was an eastern tradition that migrated to western churches. G. also gives a Latin and Greek example of hymns that were composed in the Late Roman period and are still used in churches today – ‘Of the Father's Love Begotten’ and the Akathistos Hymn to the Theotokos. G. notes that the volume is accessible for both scholars and students, but it would also be of use for anyone interested in this era.