I FIND that August is a good month to get stuck in to some serious theology. This explains why I am halfway through Sarah Coakley's essay on the Trinity, God, Sexuality and the Self (CUP, 2013), which has been hailed as a new venture in systematic theology (Comment, 18 October; Books, 7 February).

Most systematic theology is hard work, and this is, too; but it is also extraordinarily wide-ranging and imaginative, an attempt at what the author calls "théologie totale". Starting with current controversies about sexuality, she makes a series of "raids", as she describes them, into early Christianity, sociology, and iconography, and fleshes out her thinking with some fieldwork on two Charismatic communities in a northern university town.

Professor Coakley is probably the most perceptive and original theologian in the Church of England. She is also deeply engaged in the life of the Church, a late ordinand, and now a priest.

This is an invitation to recognise the link between sexual desire, desire for God, and God's desire for us. On sexual desire, we are currently stuck, of course; but Professor Coakley points a way forward that could be relevant to many other issues of conflict and deadness in the life of the Church.

She suggests that all our theology, if it is to be authentic, needs to be grounded in the bodily and mental discipline of contemplative prayer. This is where we learn to surrender control, and to begin to know God as God.

The early Trinitarian controversies uncovered an understanding of the Holy Spirit as the one who interrupts us even as we pray to dismantle our defences, and lures us more deeply into God's life. Only by this progressive transformation can we be saved from the various idolatries that hold us in thrall, whether to a sterile and conformist orthodoxy or an angry and self-righteous pursuit of our own agendas.

This is, in the best Anglican tradition, a "both/and" approach rather than an "either/or" one, but it also insists that Christian theology is empty without a commitment to prayer. In this first volume of her systematics, she has revisited the maxim of Evagrius that the true theologian is the one who truly prays.

I do not suppose for a moment that Professor Coakley would want to leave the groves of academe to be a bishop (see the parable of the trees, Judges 9.7-15). But, if she did, she would do more than make good the absence of women. She would, just as importantly, make good the current absence of a disciplined, creative theological brain in the House of Bishops.

The Revd Angela Tilby is Diocesan Canon of Christ Church, Oxford.