Often Christians behave as if their central convictions about God has little practical bearing on the world and its problems, says Simon Barrow. On the contrary, being engaged by the Trinitarian mystery of God is central to facing up to the world's lesions with realism and hope.

To some the doctrine of the Trinity looks to be modern Christianity's achilles heel in a rationalistic age, but Simon Barrow argues that it points to the coherence of God-talk as well as the challenges the Gospel poses.