The subject of exotheology has emerged in recent years as theologians have sought to frame responses to the possible discovery of extra-terrestrial intelligence (ETI). Much of the literature charts a long and varied history of philosophical reflection on the subject of other worlds from the ancient Greeks to the scientifically inspired theologies of the early modern period. Theological speculation on these problems is not new, though the scientific context may have altered. David Wilkinson is a wise, lucid and humorous guide to this literature, and he has now produced a second and more scholarly monograph to evaluate the debate. As a scientist and theologian, he is able to identify the important landmarks in the field and to explain with welcome clarity the contemporary approaches to the search for ETI. His commentary is measured and informed by an extensive knowledge of the scholarly literature. He takes us through the Drake equation and explains how to assess the probability of ETI. Fermi's paradox is considered – if they existed, they would be here. Wilkinson's own assessment is less pessimistic though cautious. Fermi's sceptical induction probably confirms that there is no ETI in our galaxy, he judges, but distances are so great that there may well be intelligent life elsewhere which is unable to communicate with us.

The theological sections of his study focus primarily on the doctrines of creation and redemption. On the first of these, he follows recent writers such as Thomas O'Meara in arguing that the creativity and love of God would in no way be compromised by the appearance of ETI. Indeed, a generous Creator might well be expected to bring about life on many different planets. On the subject of redemption, he considers two possible options. The first is the transcendent solution which argues that the significance of the work of Christ may extend across the universe to comprehend creatures of whom we know nothing as yet. The second type of solution posits multiple incarnations. Each is explored, but without the author expressing a preference for either. Finally, he points to ways in which this conversation with modern science may enrich both sides, not least for the intellectual humility that it induces in the theologian.

Wilkinson's study is the most comprehensive and reliable account of this interface available today. It will become a standard point of reference for students seeking informed study of the possible theological implications of ETI. Pointing to the seriousness of these issues, he can claim the support of scientists such as Martin Rees, who claims that this has become one of the most fascinating questions now confronting us. What Wilkinson also shows, perhaps inadvertently, is that the discussion has now become rather stuck, unable to move beyond a few familiar considerations around the doctrines of creation and redemption. We are left with a sense that new ground requires to be broken, if this debate is to move forward beyond some well-rehearsed moves. Perhaps this resides in considering the cultural, religious and ethical upheaval which would follow the discovery of ETI or by engaging with theories of artificial intelligence or by devoting more attention to the field of astrobiology. At any rate, one is left with the impression that this is an important subject, but one which now requires to be animated by some fresh conversation.