Mark Weedman explains effectively and clearly Hilary's understanding of the status of eternal Father and eternal Son and their mutual relationship: what that understanding was, how it developed and (though I doubt that this was Weedman's intention) why it is deservedly noticed only in passing by dogmatic historians. Knowledge of church politics in Hilary's time would be thin indeed without his documentation of them. He has been viewed correctly as a leading figure in the post-Nicene doctrinal settlement and as ‘rescuing the stores of Greek theology to the West at a time when the Greek sun had already ceased to warm the West’ (so Harnack amongst the scattered, but striking, lines he devotes to Hilary in the History of dogma). Yet Hilary's doctrine of God, and most of his own arguments, would have looked crude to his Greek contemporaries, did appear irrelevant to Augustine and always receive apologetic qualification from the modern historians who mention them. He ‘made great steps towards a Trinitarian theology’, strove ‘valiantly to create a satisfactory vocabulary for formulating the Christian doctrine of God’ and ‘made a permanent contribution to the theological thought of the Western Church’, so Richard Hanson in The search for the Christian doctrine of God, though how the last bit can be true after some of the negative aspects he has remarked previously is unclear. ‘Great steps’ and ‘valiant striving’ mean ‘tried hard and failed’. Weedman, ever respectful towards his author, likewise damns with faint praise: ‘Hilary attained a level of clarity about what was at stake that is unmatched by his contemporaries … if his thought does not attain the sophistication’ of, for example, the Cappadocians ‘Hilary does understand what the problems are, and he has an idea of how to solve them’; he ‘provides a window into his phase of the controversy’. These lukewarm and fully adequate observations summarise this historical treatment of Hilary's teaching from the In Mattheum prior to his exile in 356 through the Adversus Valentem et Ursacium (356/7), the De fide=De trinitate I–IV (357/8), the De synodis (358) and the De trinitate=De trinitate V–XII (359 or 360). Exile brought Hilary into the milieu of cultured Greek controversy and the circle of Basil of Ancyra. He took on board their critique of homoean doctrine and produced his own apologetical interpretation of divine unity and distinction. The culminating De trinitate is a work whose incoherences (undisguised by Weedman) are matched by obscurity of expression. He had learned enough Greek theology to make it unintelligible in Latin. What is one to say of an author who calls nativitas a substantia and ends an exposition of Proverbs viii.22 intended to prove that the Son is not a creature, by saying that the Son, as born impassibly from the eternal Father, might be called ‘a creation’ after all? None the less there are some good things. Without guidance, so far as I can see, from his Greek mentors he embarks in book xi on an eloquent and imaginative interpretation of 1 Corinthians xv.24–8 which expresses, better than anything I know of elsewhere in patristic literature, the thought that Christ is as much ‘anthropophany’ as theophany. Was he not right, too, to call Christ qua man ‘similar to’ (but not ‘consubstantial with’) us? For the Catholic Christian knows Christ as our brother and like us. It is too weak to say that the Son is like the Father, for we must mention ‘substance’ and ultimate reality; and too weak again to speak of the incarnate Lord as merely one of our own kind and not as our acknowledged kith and kin. The book has a few misprints and strange remarks, for example ‘Arius is comfortable with continuity between Father and Son on a substantive level’ (p. 124); Hilary is several times said to have ‘met’ Basil of Ancyra. Basically, though, it is reliable.