The centrepiece of this opulent work of scholarship is the text of Tatian's oration to the Greeks, swollen from thirty to a hundred pages by a German translation, critical apparatus and a commentary which suffers hardly a sentence to go by without explication. Yet all this occupies only a third of the volume, the rest of which is taken up by an introduction and five appendices, in which every question hitherto raised by scholarship is explored with minute tenacity and sound judgement. Trelenberg observes that Tatian's parenthetic and formulaic statements tell us little about his previous life or the circumstances in which he wrote the Oration (pp. 1–8). Those who assume that the death of Justin Martyr has always been an acknowledged terminus post quem for its composition will be surprised to learn that many distinguished scholars have assigned it to a date when Justin's teacher was still alive (pp. 8–10). Among them was Adolf Harnack, whose labours on the manuscript tradition, like those of Eduard Schwartz on the text itself, remain unsurpassed (pp. 18–19). After an analysis of the structure of the Oration, Trelenburg notes five salient features of its theology: the positing of God as the single origin of all things, a distinction between the emergent Logos and the eternal dunamis or power of logos; the allocation of different spirits or pneumata to all levels of reality, a copious demonology and an axiomatic belief that the human agent, as the image of God, is free to choose between damnable and meritorious actions (pp. 29–54). A polemic against the fatalistic premisses of astrology and a pervasive depreciation of Greek claims to superiority in wisdom (or even in eloquence) are the most unusual features of this diatribe; the equation of Greek deities with fallen angels, a more conventional trope, enables Tatian to show off his learning without appearing to commend the schools in which he acquired it (p. 62). The first appendix lists more than thirty parallels between the Oration and the works of Justin which, in Trelenburg's view, can leave no doubt that Tatian has taken Justin for his model (pp. 197–203): we may suspect him of circular reasoning here, as he has simply ignored the chronologies which would allow Justin to have borrowed from Tatian. The second appendix reasonably decides that Tatian is not so much a Gnostic as a Christian philosopher whose work contains Gnostic elements (p. 219). The third upholds the common and obvious view that the absence of any reference to Christ by name is dictated, as in other apologists, by rhetorical strategy (p. 224). It is equally hard to quarrel with the conclusion of the fourth, that the ‘Greeks’ of Tatian are defined by language, culture and philosophical education (p. 230). The fifth, which attempts to determine whether the work is apologetic or protreptic, is as inconsequential as any such exercise must be when it is prompted by the fissiparous habits of modern scholarship rather than by any detectable equivocation in the text.