Paul Avis has been a doughty contributor to the field of modern theology, ecclesiology and Anglican studies for several decades. His list of published works runs to nearly forty in number, according to the Cambridge University Library's catalogue. His work extends from detailed studies of particular Christian thinkers such as Charles Gore to general thematic surveys and systematic studies. It is hard to imagine any reading list on Anglicanism, ecclesiology or ecumenism on which some at least of his works would not feature. But it is in the field of ecumenical theology that he is especially well-known, not only in the English-speaking context, but on the continent of Europe where he is seen as the leading Anglican contributor to the subject. Reconciling Theology is a formidable addition to his oeuvre, even in some ways a summation of it, and an achievement already marked by the award of the Harding Meyer prize for ecumenical theology.

The opening two chapters amount to a strong ‘in principle’ case for taking seriously the study of the problem of Christian disunity, and the ecclesiological assumptions and – in Avis’ view – mistakes that bedevil the common dismissal of ecumenical dialogue as so much wasted effort: the absence of visible unity, he says, is a ‘tangible denial of the body of Christ’ (p. 14). A particular target is denominationalism, or rather the defence of denominationalism. Two further chapters are illuminating discussions of the legacy of Vatican II and of the role of church polity in theological exploration. Avis draws heavily on Hooker in the latter case, but some readers might also wonder if there isn't a residual influence of Michael Ramsey and his determination to view the order of the church as itself an expression of the gospel. In terms of structure, the book risks losing its way a little at this point, but to my mind the core of Avis’ work comes in chapters 5 and 6, in which he returns to his main theme: the urgency of reconciling different church histories and traditions as part of the necessary task of repairing the damage Christians have done to the body of Christ. The unreconciled church, Avis asserts, is a ‘counter-sign’ of the kingdom. This is some of the most passionate of Avis’ writing I have read. He scotches the idea that Christians can live comfortably with division provided they uphold a theoretical unity: ‘the church is single by definition … The Church cannot exist except as one church’ (pp. 153–4). In his final chapters he lays out a more programmatic approach to unity, in which mutual recognition as members of the body of Christ leads perforce to the church becoming a reconciled and reconciling community.

A mere summary cannot do justice to the sweep and ambition of this book. It covers a great deal of ground, and is (as always with Avis’ work) informed by a solid grasp of scholarship across a wide range of theological disciplines. For some, doubtless the sheer pace of the book will be something of a difficulty: complicated, nuanced issues are dealt with decisively and briefly; strong views are expressed pithily, and opposing views dismissed; those looking for an elaborate, patient exploration of disputed matters may be disappointed. But to measure this book by the criteria of, say, an academic monograph would be to risk missing the point. Avis’ theology is first and foremost a church theology. Its audience is not only scholars but, in the rather woolly argot favoured in church circles today, ‘practitioners’, that is, church leaders, those involved in church life at local level, those who have the capacity to influence and shape the church of the future. This is the case for the prosecution aimed against those who complacently assume division is acceptable and ecumenism an unaffordable luxury. It is almost as if one could imagine Avis speaking to an audience of church leaders who think they know something of modern theology and modern church history: he wants them to come away changed from the encounter. This is theology for practice.

Avis’ style of writing may not be explicitly polemical, but it is engaged, passionate and opinionated. At the same time, he is always careful to lay out opposing positions, and sensitive to the relevance of history to ecclesiology. Even those who do not agree with his overall position will undoubtedly learn a great deal from his discussion of authors. For that reason, in this reviewer's opinion there could hardly be a better introduction to the theological complexities of the movement for Christian unity.