From the preface to the last sentence Paul Avis challenges and guides the reader with a clarity that leaves one in no doubt that there is a serious task to be done if churches and individuals are to be faithful to Christ's prayer for unity. The opening statement that the ‘ecumenical movement is ripe for reform and renewal’ (p vii) is carried through this volume with such strength that at no point does the urgency of the argument falter. Lest that should suggest that here is a man in a hurry, Avis provides a clear and coherent narrative that engages the breadth of the catholic tradition; such is to be expected of so well respected an ecumenist and theologian. This volume betrays a deep and sensitive appreciation for and understanding of the ecclesiological inquiry that is so vital to the task of ecumenical endeavours and, of course, to canon law. Of considerable importance, however, is that Avis at no time limits his horizons to the English, Anglican context from which he comes. Instead here is a volume that recognises that the task of reshaping ecumenical theology is one for the whole Church and will require and employ a variety of disciplines, traditions and schools of theological method.

The reshaping of ecumenical theology is not simply about structures and treatises; consequently the reader is left in no doubt at each stage of this volume that the raison d’être of the ecumenical movement is to participate in the mission of the Church. This reshaping will require faithfulness and a deep concern for preserving authenticity. With this in mind Avis sets about reviewing developments in ecumenism, assessing what the authentic hermeneutics of unity should include, providing a critique of the way in which reception has been, and is being, understood in a variety of contexts, and discussing what it is that churches stand for at a time when there is considerably greater mutual understanding of other traditions. It is in relation to this last point that some of the most significant tensions in recent ecumenism appear to have arisen. On the one hand, the nature of oversight in the life of the Churches has been more honestly understood; yet, on the other, it has become a much sharper point of division than ever before. So a chapter on episcopacy offers an honest commentary on the episcopal office as understood in a number of recent texts and dialogues. This alone should be seen as an important contribution to a much hoped-for consideration given by canon lawyers to the question of oversight and authority. For at the heart of the question of polity is the one, holy, catholic and apostolic nature of Christian life, and therein one unearths some uncomfortable challenges to churches of all traditions. Perhaps more than at any other point in the book, the need for attention to the polity of ecclesial life is made here and in the following chapter on the nature of communion – the building of it and the breaking of it.

It is thus of no surprise that canonists should be found to be concerned about ecumenism as they serve the Church in the task of proclamation and presence in the diverse communities of this land. An exploration of differences on ethical teaching at a time when there is greater ability to share in common life and witness presses this point further. This very properly requires of the reader some questioning as to the limits of diversity and difference while preserving the bonds of unity and peace. Undoubtedly this indicates the ground for future work and another point at which articulation of polity will be vital.

It is these later issues that underline that canonists can and do make a valuable contribution to the ecumenical task, and this volume will provide an essential resource to all who seek to apply the study of canon law to the call to greater unity. Avis, however, makes little reference to the place of canon law. This is not underlined so as to be critical: canonists must bear some responsibly for such an absence. What this book offers is the chance to enrich a conversation and develop work that is already in place, thanks to the efforts of the Colloquium of Anglican and Roman Catholic Canon Lawyers. That a number of ecumenical agreements have brought Churches to a greater sharing of common life has very properly required that attention be paid to the canonical consequences. The examples of where incorporation of some agreements into canon law has taken place (the Porvoo Agreement and the Covenanted Churches in Wales) will require further attention if the fruits of ecumenism are to be developed further. Canonists should be essential participants in any ecumenical dialogue as both disciplines have at their heart the articulation of ecclesiology and the faithfulness of a common life.

Avis ends with notes of realism and challenge. Calling churches and individuals not to rest on the laurels of success, he presents the challenge to continually broaden the sphere of fellowship. In such a task the richness of this volume will be an invaluable guide.