Undergraduates and their teachers will find this a useful, lively, and, on the whole, reliable introduction to the early history of Christianity in Rome, its materials and its problems. Though it will not supplant Peter Lampe’s From Paul to Valentinus, English readers will find it more accessible than that book in its English dress. Green’s focus on Rome does not prevent him from bringing in much material about Christianity in other parts of the Roman empire, though more frequently from Latin-speaking parts than elsewhere. Similarly, the titles of the five chapters—origins, community, persecution, catacombs, and Constantine—are not narrowly conceived, but serve as pegs from which discussions of related matters are hung. Early Roman theology, for example, is discussed under ‘Community’, ecclesiology under ‘Persecution’, and the origins of Christian art under ‘Catacombs’. There are useful, sometimes abundant, references to ancient sources and to modern discussions. Perhaps because of the book’s origin in lectures addressed to undergraduate students and in tutorial discussions, Green’s treatment is sometimes uneven and idiosyncratic. For example, he provides a sensitive, even sympathetic, discussion of Marcion and Valentinus (pp. 62–81) but a rather less focused account of debates within mainstream Christianity about the Trinity. ‘Monarchians’, we are told, ‘left no writings; indeed there is little sign at all that they put their ideas down on paper’ (p. 103). This seems to rest on the view that ‘Monarchians’, or opponents of ‘the Logos doctrine’, comprised only those ‘known to their critics in the West as Patripassians … and in the East as Sabellians’ (p. 102). Dionysius, bishop of Rome c.259–68, was not a Sabellian, but that did not stop him from describing the monarchia as the ‘most august proclamation of the Church’, nor from attacking those who would destroy it by dividing and dissecting it into ‘three powers’ and ‘separate hypostases’ and ‘three divinities’. Green refers to Dionysius’ correspondence with his namesake at Alexandria on this issue (p. 168), but does not quote from it or discuss it, and says simply that ‘he despatched a formal statement of trinitarian belief which anticipated the debates of the next century in which he would be quoted’.