The Christian reception of the voluminous works of the Greek-speaking Jew, Philo of Alexandria, has been a subject of some discussion. One thinks in particular of the doyen of Philonic studies, David Runia's publication of 1993 as well as other studies focusing on the reception of Philo in a single author. Jennifer Otto's publication adds a new dimension to these studies. Taking as her subject the reception of Philo in Clement of Alexandria, Origen and Eusebius, she seeks to show how these authors’ citations of Philo ‘reveal ongoing efforts by Christians to conceptualize and demarcate the difference between two emerging but fluid collective identities, “Christianity” and “Jewishness”’ (p. 4). The emphasis of Otto's study is to some extent of the moment, as she indicates in her introductory chapter. Scholars interested in ancient Jewish-Christian relations have become increasingly aware of the constructed character of these two identities, of the complex character of their interaction, and Otto's study can be said to constitute a contribution to this growing area of interest.

The book divides itself into four main chapters. In the first of these Otto questions what has become the standard view, that Philo's works were transmitted from the Synagogue, perhaps from a school presided over by Philo, to the Christian Church. In what is an innovative and compelling chapter, she suggests that there are good grounds for thinking that these works could have been transmitted to Clement of Alexandria, our first known user of Philo, through philosophical study circles which emerged in a number of places within the Roman Empire. When Clement calls Philo a Pythagorean, as he does on two occasions, this might well reflect the context in which he first read Philo, one which was not Christian or Jewish, but pagan and philosophical – in this view Clement's familiarity with Philo does not evidence continuity between Jewish Synagogue and Christian Ekklesia. Such a thesis is not only suggested by the haphazard way in which philosophical works were transmitted in the empire but also by the fact that Alexandria was a well-connected, international city, that Clement travelled, and by evidence of wider interest among philosophers in barbarian wisdom, and in the case of a writer like the Syrian, Numenius, in the Hebrew Bible.

The next three chapters are dedicated, respectively, to the use of Philo in Clement, Origen and Eusebius. In each case Otto begins by assessing the way in which the individual author uses the term ‘Jew’, ‘Hebrew’ and ‘Israel’, as a way of elucidating their understanding of Jewishness. The respective chapters then move to a focus upon the individual instantiations of the use of Philo and how they relate to the individual author's understanding of Jewishness. The conclusions, predictably, vary. Clement uses Philo as part of a wider argument about the claim that the Church teaches true knowledge, given to it by the Logos, Jesus Christ. Philo's exegetical methods and assumptions are not dissimilar to those of Pythagoras, and this may explain why Clement describes him as such. Whether Clement saw Philo as a Jew is left open by Otto, not least on the basis of what she has already argued about the context in which Clement may first have read Philo's works. Interestingly, she notes that, as a Pythagorean, Clement would have understood Philo as not dissimilar to the way he understood a Hebrew, that is, someone close to true gnosis, but not quite there. The section on Origen follows. Insofar as Origen mentions the name of Philo, and he does not do so often, the latter emerges as a respected exegete, someone who supports Origen's own allegorising of the Scriptures and so aids the latter in his attempts to defend a sophisticated reading of them. Origen is critical, however of the fact that Philo's hermeneutical assumptions do not lead him to question the legitimacy of the Torah. For this reason, Otto suggests, he never refers to Philo's exposition on the law. The final chapter on Eusebius shows how the church historian seeks to use Philo to support a view of the Hebrews as the origin of philosophical wisdom and a support to a Christian politeuma which disregards the Torah. Philo also plays a role as a witness to Jewish suffering and difficulty, which Eusebius exploits for polemical purposes. Otto also presents Eusebius as keen to use Philo as what Otto terms ‘an impressed observer’ of Christianity, here emphasising his claim that Philo met Peter in Rome and that his warm-hearted description of the Therapeuts was in fact a description of a Christian group known to him.

In a final chapter of conclusions, Otto notes that all of the writers whom she has examined found it difficult to fit Philo into what she terms their ‘binary categories’ of ‘one of us’ and ‘one of them’, or put another way, their understanding of Christianity and Jewishness, to return to the central concern of the book. In that respect Philo was a troubling character, but one who was able to mediate between the categories of Christian and Jew ‘while ensuring that the two identities remained rhetorically and conceptually distinct’. This troublesome aspect to Philo was to grow in its significance, leading subsequent writers either to appropriate Philo as a Christian or to be more explicitly critical of his Jewishness.

This is a fascinating book which in a small compass covers a lot of ground. Its excellence lies not just in the overarching conclusions that it draws, but in many of the individual discussions which form its core. The perspective from which it comes at the question of the reception of Philo, which can in the hands of some be a rather dry and uninteresting exercise, taken up with highly detailed tabulation, is intriguing. The juxtaposing of the individual authors’ understanding of Jewishness with their actual treatment of Philo the Jew helpfully serves to articulate the problem with which Otto is concerned, as one stands in tension with the other. It is, of course, the case that the demarcation of Jewishness and Christianity in relation to. Philo is more obviously a subject of discussion in the case of Origen and Eusebius than of Clement, who, according to Otto, remains unclear about Philo's identity as a Jew, a conclusion which contradicts the scholarly consensus. However, it was unclear to me after reading this book how much thinking about questions of identity emerged even in Origen's and Eusebius’ engagement with Philo. He may have been portrayed as a binary-breaking problem but he is that by implication rather than explicitly, and the failure in particular of Origen to refer explicitly to him that much raises questions about how much thinking about these issues Origen was in fact engaged in. In this context I was also struck by the absence of much use of Philonic allegory about the law. That it was known that Philo remained a Jew was hardly grounds not to cite his highly articulate allegorical engagements with the Jewish Torah and its practices, with all the use to which Christians could have put these. Indeed, as I recall, Clement cites some of Philo's more positive comments about the law but without referring to him explicitly. I also wondered whether more could not have been made of the absence of references to Philo before Clement. Their very absence, and the lack of evidence of knowledge of his works by Christians, even by allusion or quotation, might have added something to Otto's views about the origins of Clement's knowledge of Philo. Something might also have been said about the use of Josephus by the writers with whom Otto is concerned. Clement does not mention Josephus explicitly, but Origen and Eusebius do, and Origen is more explicit about Josephus’ lack of belief than he is about Philo's. Was Josephus’ Jewishness negotiated in a different way from Philo's? And to what extent is an answer to that question affected by the use to which both writers were put? Finally, one wonders why Philo's Jewishness became more problematic to writers after Eusebius. Had the antagonism between Jewishness and Christianity become more firmly established by then?

These are but a few questions elicited by a stimulating and thoughtful book.