Discussing the philosophical sources of ancient Christian thought, most of us are usually content with the dictum that its development in terms of philosophical arguments was governed by Platonism. As a welcome antidote to such simplification, E. sets out to show that Peripatetic thinking, especially the interpretative tradition of the Categories, also exerted deep influence on major figures of early Christianity.

The book is organised into chapters highlighting stages and authors where effects of Aristotelianism are particularly well detectable. After the introductory chapter on Aristotle, indicating the points that were to be of great interest for Christians, E. describes the fate of Aristotle's doctrines in the second century ce, with an emphasis on the reaction to them by Atticus and Alexander of Aphrodisias. Among others, he points out Alexander's innovations on the Aristotelian picture such as the notion of sublunary providence, privation as the fourth cause, the role of productive intellect in the acquisition of knowledge and, based on the Commentary on Aristotle's Metaphysics 12, the clear distinction between divine and human intellect. On this last point one might raise doubts about the authenticity of this commentary given that Alexander's commentary on Metaphysics 6–14 seems to have been lost and the text the CAG editor has adopted comes from Michael of Ephesus, the twelfth-century Byzantine commentator (see, also with further references, I. Kupreeva's contribution to Der neue Ueberweg. Die Philosophie der Antike 5/1, §39, p. 387).

The next century saw the widespread, and sometimes idiosyncratic, reception of Aristotelian ideas by Christian authors. E. has shown that Tertullian's use of substantia originated, not in Aristotle, but in a disciple of Paul (Hebrews 1:3), that Hippolytus of Rome's strictures on Aristotelian logic are not crude blunders but able sophistries and that Clemens of Alexandria drew mainly on the exoteric works of Aristotle. He also suggests that the main source of Origen for Peripatetic philosophy was Alexander of Aphrodisias. The useful comparisons between their theories, for example concerning μὴ ὄν, the necessary and the possible, indicate striking parallels, even if the two authors have different points of departure; in Origen's case it is the Scripture. The Peripatetic legacy is also transparent in the vocabulary that the Christian theologian applied to interpret those notions. Among Aristotle's works, the Categories left a significant impact on intellectuals of the era, Christians and Pagans alike. Plotinus’ critique of Aristotelian and Stoic categories and the exposition of his own views (Enn. 6.1–3) served as a preliminary for Porphyry to harmonise Aristotelian and Platonic notions. He translated the discrepancies that Plotinus had exposed into a fruitful complementarity; the Categories implies an ontology, but it was intended to govern the world of senses only. The fusion of Aristotelian and Platonic theories made some of Aristotle's ideas and his vocabulary more palatable to Christian apologists. The terms οὐσία and δύναμις were central in the Nicaean disputes on the nature of Trinity and the competing parties drew on pagan theories to substantiate their claims. This is especially evident in Marius Victorinus, who also employed the concepts of potentiality (Father), first actuality (Spirit) and second actuality (Son). Augustine was familiar with Victorinus’ writings, which may have inspired him to treat the mind as a paradigm for Trinity. It does not mean, however, as E. emphasises it, that the background of his theory of words is to be found in the Categories and Porphyry's commentary, just as his remarks on time get support from Aristotle's notion of the ‘mystery of the elusive now’. On the other hand, E. is rightly cautious about the assumption that important theses of Augustine's trinitology were inspired by Aristotle's Metaphysics 12 and the Categories. Instead, he points out an important analogy; the object of vision is the Father, the image is the Son and the intention or will conjoining the two is the Spirit.

A substantial part, carrying many novelties, of the work is Chapter 6, where E. discusses the extent to which Gregory of Nyssa is indebted to Aristotelianism. Gregory had to respond to Eunomius’ intricate arguments for the essential difference between Father and Son, and creation of the latter by the Father's will, not his nature. The response reveals the familiarity with Porphyry's thesis on the inseparability of God's δύναμις from his οὐσία and with the Aristotelian antecedents for the notion of ἄπειρον (although here, on p. 106, I would prefer ‘undetermined’ for translating ἀόριστος). The discussion of the use of Porphyry's interpretation of the Categories in Basil of Caesarea(?)'s Letter 38 is illuminating, just as the portrayal of the Cappadocian critique of the notion of the Son as an image of the Father. The chapter closes with a thorough examination of the term ὑποκείμενον, an entry sadly missing from Brill's Dictionary of Gregory of Nyssa. Aristotle was never quoted in the fifth-century disputes on the nature of Christ, but his logical vocabulary was used frequently in the texts that preceded or followed Chalcedon. Defenders of the Chalcedonian creed had to explain how a concrete subject can have two natures, or two οὐσίαι, and they made use of Aristotelian terminology. One of the key people in the development was Emesius of Nemesa, but the main emphasis is on the approaches to explain Christ's nature. E. contests the rigid classification according to which the two heresies that the Chalcedonian formula of ‘one person in two natures’ was designed to exclude can be labelled as the Antiochean and the Alexandrian. He indicates the scarcity of evidence for such an assumption, especially for the thesis that Aristotle was a much cultivated author in Antioch. Moreover, a careful study of Leontius of Byzantium, a supporter of Chalcedon, reveals that his knowledge of Aristotle's logic was superficial.

Nowadays, John Philoponus is far better known as a commentator of Aristotle and philosopher in his own right than as an apologist, and E. draws attention to his views in theology (but I would not insist on a bifurcation of the whole corpus into two phases, see P. Golitsis, Les Commentaires de Simplicius et de Jean Philopon à la Physique d'Aristote [2008], pp. 27–37). Although in his views Plato's theory is closer to truth than Aristotle's, Philoponus adopts many Aristotelian theses, mostly in physics and psychology. E. analyses the argument in On the Intellect (a commentary on Aristotle's On the Soul 3.4–8, preserved in Latin) against the contention that the active intellect is God himself. He shows how Aristotle was taken to subscribe to the Christian view of the afterlife, involving also a temporal origin of the world, a fully anti-Aristotelian thesis. As a theologian, Philoponus rejected both the Nicaean dogma on the unity of the Godhead and the Chalcedonian creed on the dual nature of Christ. E. points out a number of Aristotelian elements, in terminology and doctrine, that were used in exposing such views. He also calls Boethius the Philoponus of the Latin Church, and rightly so, though the former's views were not so blatantly heretical as his elder contemporary's in Alexandria. Through a survey of his commentaries on Porphyry's Isagoge and on Aristotle's logical works we can see how Boethius draws on pagan material to prove the incorporeality of God. E. also shows how the Christian heritage determined the arguments for divine foreknowledge. Although the Consolation lacks any explicit reference to the Scriptures, it treats the problem in a way in which it could not be phrased by a disciple of either Plato or Aristotle.

E. has managed to show both the importance of Aristotelian doctrines in the formation of Christian theology and the limits of their influence. This volume should be consulted by anyone with an interest in the subject.