Studies in the thought and culture of St Gregory of Nazianzus (c. 329–90) (known throughout the eastern Church as Gregory the Theologian after this title was given to him at the Council of Chalcedon) have come a long way since G. L. Prestige casually dismissed him as a ‘dignified populariser’. Although the complete critical edition of his works (scattered almost upon completion in 1939, when the Nazis assassinated so many Polish scholars) still remains to be achieved, critical studies have accumulated through the last two generations to make it clear that here indeed was one of the most learned men of his generation, and a theologian of immense subtlety and sophistication. The present work, originating as a 2016 St Andrews doctoral dissertation, is a welcome and worthy addition to that literature. It is elegantly and fluently written and deeply familiar with the primary texts and the commentators. It focuses on the manner in which Gregory's doctrine of the Spirit (he was one of the most insistent of the neo-Nicene movement on the Homoousion of the Spirit and has a correspondingly profound doctrine of the Trinity) forms the backbone of his understanding of salvation offered in Christ, and through Christ effecting reconciliation with God the Father. This concept of the Transcendent's outreach to the immanent world (the relation of the one to the many) was a preoccupation of other sophists of his age, but Gregory shows a remarkable synthesis of philosophical, biblical and ‘inspirational’ notions to advance a particularly Christian understanding. Langworthy shows that the defence of the divine being of the Spirit was Gregory's lifelong mission: one resisted to a degree by more cautious protagonists at the Council of Constantinople in 381, but coming to a fruition in Gregory's Oration xxxi and Carmina arcana poems which he polished and published in retirement. He joins together the burgeoning ascetical turn of Christianity to make it clear that the metaphysics of salvation offered by God in Christ were individually appropriated through the progressive purification of a person's mind and life-style, in what he called (coining the term for the Church) Theiopoiesis. Gregory conceives of the Spirit ‘as a being that was, undertook, and possessed perfection – holiness – by nature’ (p. 164). Salvation was the acquisition by the believer of this indwelling presence. Gregory's most vivid sense of the ecclesial aspect of salvation, we learn, is the way in which he sees as critical the need for Christian leaders to exhibit the Spirit's presence. His very low estimate of the quality of his episcopal contemporaries is often displayed in withering verses, which give a sense of how, still emerging from the bitterly disruptive Arian crisis, he saw the Spirit's mission as most clearly needed in his own time.