This monograph, originally a thesis supervised by Christoph Markschies and submitted at the Theological Faculty of the Humboldt University in Berlin, offers a thorough study of Tertullian's short treatise Against the Valentinians. In part A (pp. 1–116), a careful introduction to Against the Valentinians, Kingreen kicks off by announcing the analysis of the rhetorics of Against the Valentinians as the main focus of her study (pp. 2–6). A short chapter first surveys the work of scholars such as J.-C. Fredouille, and R. D. Sider with a similar focus on rhetorical analysis, before identifying a second line of inquiry: recent scholarship has tried to explore Against the Valentinians for clues about the origins and development of Valentinian Gnosticism and its various versions (pp. 7–10); Kingreen intends her study as contributing to that inquiry. Chapter iii of part A rehearses our knowledge of Tertullian and his educational background (pp. 11–27), while chapters iv–vi present the main results of Kingreen's rhetorical analysis of Against the Valentinians (pp. 28–77): the treatise combines an overlong exordium with a narratio which also serves as a refutation (p. 52: ‘widerlegende[r] Darstellung’). Or, as Tertullian himself succinctly puts it in Against the Valentinians 3.5: ‘merely to show is to destroy’ (‘etiam solummodo demonstrare destruere est’). Accordingly, Kingreen rejects the suggestion of, inter alios, Fredouille that Against the Valentinians is somewhat unfinished and that – following the example of Irenaeus of Lyon in Against the heresies – it was to be complemented by a proper refutation. For a polemical presentation revealing in one form or the other the absurdity of its subject matter one could cite – apart from Irenaeus Against the heresies 1 as the immediate model – other ancient examples, such as Plutarch, On Stoic contradictions. Building on the excellent work of Fredouille and others, Kingreen convincingly demonstrates that Tertullian's rhetorical strategy amounts to a creative adaptation of classical models, particularly Cicero. According to Kingreen (p. 275), the irony of Tertullian's narratio – building again on Irenaeus (Against the heresies 1.9.5; 1.11.4) – exposes for the benefit of his educated Christian readership (pp. 78–80) the Valentinian myth as a hybrid piece of stagecraft, combining tragedy and comedy in sordid and decidedly lowbrow fashion (pp. 74–7). Informed by Cicero, Tertullian is well aware of the pitfalls of rhetorical ridicule (pp. 60–73), which, as Kingreen correctly stresses, he uses as a psychological means to strengthen Christian group identity. Her suggestion, however (p. 73), that Tertullian paradoxically enjoins on his audience a binding obligation to laugh (‘verpflichtenden Aufgabe zu lachen’) surely forces the meaning of Against the Valentinians 6.3 where Tertullian simply defends his relentless ridicule against the possible criticism of a readership familiar with his classical models. Kingreen deals in some detail with the question of possible sources (pp. 94–116): in Against the Valentinians 5.1 Tertullian the Montanist construes a genealogy of heresiological expertise, citing as his predecessors in climactic order Justin Martyr, Miltiades the Sophist, Irenaeus of Lyon, and – this is to enhance the intellectual reputation of his Montanist brethren – ‘our Proculus whose excellence joins the virginity of his old age to Christian eloquence’. It is, however, probable, Kingreen argues – endorsing here the view of, amongst others, von Harnack – that Tertullian drew for his narratio solely on Irenaeus, Against the heresies i.1–8 and i.11ff (pp. 99–108). Kingreen advances this particular hypothesis with a dose of understandable caution: the complex task of a synopsis of the texts of Irenaeus (both the Greek fragments as transmitted by Epiphanius of Salamis and Ephraem Graecus and the fourth/fifth-century Latin translation) and of Tertullian is explicitly left outside the purview of her monograph (p. 101). In any case, Tertullian's Latin adaptation constitutes not only an important witness to Irenaeus' original text (p. 100), but also – for all the entertaining rhetorical fireworks – an attempt to understand it and its subject matter. It is quite possible that in the second and third centuries the versions of the Valentinian myth confected by heresiologists such as Irenaeus and Tertullian reached a larger audience than the writings of the various ‘Valentinian’ teachers themselves – and at least some readers may have been more interested in the ideas of the Valentinians than in the refutations of their ‘orthodox’ counterparts. Part B (pp. 117–54) presents the Latin text of Against the Valentinians with a facing German translation. Both the readings of the Latin text and the translation are justified in great detail by the commentary of part C (pp. 156–448) where Kingreen is in constant dialogue with her predecessors, particularly A. Marastoni, J.-C. Fredouille and C. O. Tommasi-Moreschini. The textual criticism is, as far as I can see, cautious and keen on avoiding unnecessary conjectures if possible (for example, p. 173 n. 1, where the reading ‘facili claritati’ in Against the Valentinians 1.3 is defended). Translating Tertullian's sophisticated Latin into a modern language is clearly a daunting task. Where I have checked it, Kingreen's German rendering of Against the Valentinians has turned out to be competent and reliable, leaving room for the occasional disagreement. For example, Kingreen's translation of 4.1 ‘testatio est ipsa mutatio’ as ‘Denn Bezeugung als solche ist immer schon Veränderung’ (p. 121) seems to switch subject and predicate noun; Tertullian here explains that the very fact that Valentinian doctrine has evolved testifies to its origin. Kingreen's rich commentary defies easy summary. The passage Against the Valentinians 4.2 has been taken by several modern scholars as a possibly valid explanation of the doctrinal difference between Valentinus and his disciple Ptolemy: ‘Eam postmodum Ptolemaeus intravit, nominibus et numeris aeonum distinctis in personales substantias sed extra Deum determinatas quas Valentinus in ipsa summa divinitatis ut sensus et affectus, motus incluserat.’ Valentinus' ‘monohypostatic’ doctrine of God (which included the eons as affects and emotions in the Godhead) here appears to be somewhat pluralised by his disciple Ptolemy (p. 228f). Kingreen does not seem to commit herself as to the historical value of this passage; she observes, however, that the talk of personales substantias is echoed in Tertullian's Against Praxeas (p. 230). Already Fredouille had noted in his commentary ad locum further parallels, such as Against Marcion 1.25.2; 2.16.2 etc. Since De praescriptione haereticorum 7.3.5; 33.8 credits Valentinus with the very doctrine that Against the Valentinians attributes to Ptolemy and his disciples, it is, in any case, very risky to exploit this passage for the inner history of Valentinianism. A propos of Against the Valentinians 12.2f. where Tertullian mocks the pacified Valentinian pleroma of eons by comparing it to the scandalous jollity of a shipmaster (nauclerus) and his crew (nautici), Kingreen justly evokes the parallel designation of Marcion as nauclerus (p. 305 n. 228: Tertullian, Against Marcion 1.18.4; 5.1.2; praescr. 30.1). I have tried to argue elsewhere that Tertullian's may indeed use nauclerus also in this case as a sobriquet. Kingreen's monograph should be consulted by all those who are interested in the literary culture of Roman Africa, early Christian heresiology and the history of Gnosticism.