If it is a critic's business to cavil, this book will be the despair of reviewers. It commences with a chapter on the definition of Gnosticism, in which Brakke justly notes that many scholars have advanced heuristics recipes as factual descriptors and have failed to see, in defending them, that coinages of this kind may be more judicious than their rivals, but not simply more true or false. Whereas King and others ascribe the babel of modern tongues to the confusion of the Fathers, Brakke proves summarily that the usage of ancient writers is consistent and is unlikely to be malicious, since they never say ‘we call these deviants Gnostics’, but ‘they call themselves Gnostic, though we have other names’. In the second chapter he finds that the texts which the Fathers and Porphyry recognise as Gnostic are for the most part coextensive with those which modern commentators have styled Sethian, substituting this less widely-attested term for ‘Gnostic’ because they feared that the latter had become too protean for scholarly employment. Conceding that the Naassenes do not fit this pattern, he argues that (like Clement of Alexandria) they applied the label ‘Gnostic’ to themselves as an epithet rather than a proper designation. In chapter iii he examines the tenets and practices of the Sethians, who are distinguished by their apophatic theology, their veneration of Seth as firstborn from Adam, the myth of the fall of Sophia and the (still unfathomed mystery) of the five seals. He contrasts them in chapter iv with Valentinus, whose original teachings, so far as we can recover them, appear to have been grounded in the writings of John and Paul and did not presume an eternal dichotomy between matter and the Godhead. He sets Valentinus against his contemporary Justin Martyr, not as a heretical against an orthodox visitor to Rome, but as one of numerous branches from the same biblical stock. He repeatedly assures us that in arguing for a Christian origin of Gnostic thought against those who would trace it to an unattested cabal of embittered Jews, he is not upholding the Irenaean view of Gnosticism as an aberration from the apostolic doctrine. It was only, as he explains in chapter v, the formation of an ecumenical episcopate that made it possible for the partisan of any Christian group to regard his own as the catholic teaching and the rest as heterodox. I differ only in believing that Irenaeus represents pretensions that had already been maintained by the episcopate for two generations before him. I also wonder whether it is fair to hold up Origen and Clement of Alexandria as paladins of autonomous speculation whom the episcopate wished to suppress. Origen was a mouthpiece for the bishops, and if he found some holders unworthy of the office that does not entail that he thought the office contemptible. It remains true that few studies of the Gnostics say so much in such brief compass, and so little that is exposed to fatal objection.