Christopher Beeley's book is a scholarly piece of historical theology, setting Gregory's concerns and aims in a detailed context, but also grappling with his complex theology in a way which moves beyond historicism. As the title suggests, the book focuses on Gregory's trinitarian theology. However, one of its major aims is to reunite certain aspects of Gregory's theology which have tended to be studied apart: notably, his trinitarian theology, epistemology, Christology and soteriology. Beeley successfully shows that each of these is illuminated when considered as part of an interconnected network of thought, rather than as isolated dogmatic propositions.

After an introduction with a detailed account of Gregory's life and works, Beeley deals with the nature of theology in Gregory's writings: or, more accurately the nature of the theologian in relation to God. Christian theology ‘begins not with abstract information about God . . . but with the transformation of the theologian within the horizon of God's presence’ (p. 64). For Gregory theology, a ‘dialectic of purification and illumination’, inextricably links knowledge of God to ‘the condition of the knower’ (p. 63). It both demands of the believer a commitment to change through purification and causes a transformative change: illumination. Beeley explains complex concepts clearly without sacrificing subtlety. For example, he emphasises the role of faith in the purification–illumination dialectic and he notes both continuities and discontinuities with Gregory's antecedents (particularly Origen and Plato). Beeley argues that Gregory's first-person narration of Moses’ ascent up Mount Sinai emphasises bishops’ theological authority; but Gregory's warning that ‘philosophizing about God is not for everyone’ (Oration 27, pp. 66–7) is set alongside an intelligent analysis of Gregory's concepts of theoria, praxis and philosophia which shows their wider applicability within the Christian community. Beeley also gives a well-judged answer to the question of to what extent Gregory of Nazianzus is an apophatic theologian.

This chapter sets the tone and method of the rest of the book: an integrated reading which seeks to correct various perceived misinterpretations of Gregory's theology. Thus, in chapter 2 Gregory's Christology is contextualised within his soteriology so as to bring out its anti-Antiochene as well as anti-Apollinarian motives. The tricky notion of divinisation is treated subtly in chapters 2 and 3: the latter stresses the notion of the Spirit's indwelling in the church and critiques earlier treatments of religious ‘experience’ in Gregory's theology. Chapter 4 on the Trinity contains a helpful analysis of the terms monarchia, oikonomia and theologia in Gregory's thought, with a particular eye on how they have been (mis)read in modern accounts of the ‘economic’ and ‘immanent’ Trinity. A fifth chapter on ‘pastoral ministry’ examines the practical and sacramental outworkings of the preceding theology, with some particularly interesting reflections on training (both human and divine) and the reading of scripture.

The conclusion draws together the analysis of Gregory's work by comparing it with that of such theologians as Origen, Athanasius, Apollinarius, Basil and Gregory Nyssen. Some of these comparisons are on less firm ground: it seems possible, for example, that through a similar integrative reading a ‘two models/grammars’ approach (see pp. 226–7) could be usefully applied to the other two Cappadocians as well (without suggesting the theologies of the three are identical). There is present in the book a slightly defensive attitude to Nazianzen which I am not sure is entirely justified: although there has indeed been a boom in Nyssen studies, the other Cappadocians have hardly been neglected, and it is Nazianzen who has tended to be lionised by the more theological writers on the Fathers.

In sum, this is an impressive first monograph, with insights and new interpretations for the specialist, but also of great use for advanced students as a thorough exposition of Gregory's theology.