This modest contribution to the history of ideas instructs positively and negatively. It discloses a chain of theologies from Aristotle (through Plotinus, the Cappadocians in controversy with Eunomius, Ps-Dionysius, Maximus) down to Palamas; the relationship of God to World (for the Christians, of God to Christ and to World) being explained through the notions of ‘activity’ (ἐνέργεια), ‘participation’ (μετουσία/μέθεξις) and the like. Yet it also (I verge upon the moot) reveals the impotence of these concepts to explain the relationship (or better, ‘the alleged relationship’) of absolute and ineffable deity with created ‘otherness’. As Tollefsen rightly and eloquently puts it, if the Greek tradition is followed in full seriousness ‘there is only room for a theology of complete silence’. (A whiff of Valentinus’ Σίγη). ‘God himself breaks the silence by establishing an economy of complete otherness’ (a whiff of Hegel) ‘with regard to Himself’…Theology ‘moves in the sphere of otherness’ with ‘different strategies for talking about’ the ineffable. The criteria for correcting these strategies come from ‘“what comes after God”’ in ‘His revelation’, which ‘is an activity executed in created being’. ‘Activity’? Tollefsen sees ἐνέργεια in its variety of senses of ‘action/act/fact’, as derived ultimately from Aristotle for whom it is inapplicable to God as final but not efficient cause. Plotinus, allowing for an intra-divine and extra-divine ἐνέργεια, exploits the Platonic notion of ‘participation’ to furnish something similar to the Christian theology of voluntary ‘creation’. Eunomius’ theology, rejecting ‘participation’ to explain divine creation distinguishes ingenerate divine substance (οὐσἱα) from divine ἐνέργεια and explains the distinction as a ‘following’ of ‘activity’ upon ‘substance’. The distinction was seized upon by the Cappadocians and critically manhandled but the three terms, explanatory of creation, re-creation and intra-divine life have at this point entered the tradition and the rest of the history is their exploitation, with important expansions and glosses from Ps-Dionysius and Maximus, to yield an account of the World's creation as (at this point we verge again upon the moot) the participation in divine ἐνέργειαι which are really distinct from the divine οὐσἱα. The theology entails inconvenient consequences into which I will not go. I think Tollefsen believes them tolerable and inevitable. Perhaps he is right. The book's title misleads: Maximus and Palamas are scarcely from ‘early’ Christianity. But Tollefsen has written elsewhere authoritatively on Maximus and it is good to have his further thoughts here; Palamas can be understood to complete the Greek Fathers as perhaps Aquinas does the Latin. The theologies discussed are exclusively graecophone. Augustine and Thomas Aquinas are mentioned in passing, coolly and without the ‘saint’ attached to Basil, Gregory of Nyssa and the rest. ‘Greek and Latin Christian thought represent two different kinds of ontologies. However, I cannot see that the ancient Greek Christian thought lacks in philosophical virtues compared with its alternative.’ Again, perhaps he is right, though you have to be able to endure ‘partake of reality’ as = ‘exist’ et al. and Maximus’ apophaticism which makes Basilides seem a dogmatic rationalist. When Tollefsen writes ‘obviously’, as he often does, he means ‘conjecture follows’.