The title of this volume may seem to many to express a paradox and to suggest that the contents will be written either as satire or in fury (or both). However, thanks in no small measure to the indefatigable efforts of the editor, we can reflect that (in the words of Pope Francis) ‘canon law is not only an aid to the ecumenical dialogue, but also an essential dimension’. These papal words are quoted in this volume by the Grand Ecclesiarch Aetios – already a step forward ecumenically.

The occasion of this work is the Statement of Principles of Christian Law produced by a Panel of Experts in 2016 (which is helpfully reproduced as an Appendix), and the various authors come from ten different Christian traditions and reflect on that Statement in the light of their own tradition. The history behind this statement is given in the introductory essay by Norman Doe, and a further reflection on what it means to offer principles is offered in the conclusion by the Grand Ecclesiarch: the idea of principles draws on the legal tradition of maxims and offers a way of looking at legal systems that is sufficiently high level for points of commonality and contact to be visible. And it is remarkable how many of the contributors both note this contact and admit to being a little surprised by it: an engaging example is Paul Rochester's comment from a Pentecostal perspective that ‘denominations probably share more in common on church law than is generally thought to be the case’, but the same point is made in almost the same words by Astrid Kaptijn who writes out of the tradition of the Eastern Catholic Churches.

Each contributor in the main body of the volume first offers a sketch of the church law system of their own tradition, and these are uniformly informative and engaging. The notion that canon law is applied ecclesiology (a notion familiar to the students of this journal's book reviews editor) is both used and verified by these contributions. One example of particular interest is the account of Methodist law and discipline by John Harrod, who illustrates how the principles of connexionalism and corporate episcope operate as foundations for Methodist structures. In the wider context of receptive ecumenism, these short accounts offer a fruitful path to better mutual understanding, but they also raise some important questions. The stress of the Reformed tradition (stated several times from different perspectives in the volume) that law in the church is ‘not simply a body of rules and regulations like any other, but concerns the church as ‘creatura Verbi’ (to use the formulation of Leon van den Broeke) offers a challenge to Christians of other traditions – and I think of my own Catholic tradition in particular – to show how our own laws are thoroughly rooted in the Scriptures: we might ask ourselves whether our stress, important as it is, on the role of divine law at certain key points in our legal system obscures the way in which the whole system is the unfolding of a Scriptural and sacramental vision of the Church striving to be faithful to the Lord in every aspect of its law (and of course, constantly examining whether that is a claim which we can credibly make).

Another valuable dimension of these surveys is the way in which they are informed by the history of each tradition. This is evident not merely in the way that the specifically legal tradition is examined – Nikos Maghioros offers a superb survey of the canons of the early church from an Orthodox perspective, and the influence of the Dort Church order of 1619 is visible in most Reformed contributions – but the way in which the legal system interacts with the whole life of the church. In this context John Chalmers's survey of the way in which the life of the Church of Scotland has influenced its living out of the Presbyterian tradition is outstanding, and surely offers a pointer to further work in each tradition. This is not simply a matter of looking at the way in which human situations (and all too often human frailties) have influenced law, but of going on to see how a new ecumenical situation might offer a new way of looking at past situations and from that a new way of approaching the structural issues that have emerged from those past issues.

A particular example which struck me was the careful examination of the gradual move of the Lutheran Church in Norway towards disestablishment. Andreas Henrikson Aarflot sets this movement in the context of Luther's assertion that law is a matter for the state not the church: what then, we might ask, should be made of the regulation that exists in a post-disestablishment church? Should it still rest on a state foundation (as seems to be implicit in the Church of Scotland Act described by Harrod)? Or is the church now to be seen as an independent legislator? And if so, how will this flow back into ecclesiology? The idea of a church as the nation at prayer (in Norway expressed as the notion that the Lutheran church is a ‘folk church’) is not merely a reformed idea: as we move into a world in which church and state move ever further apart discussion could usefully ask how much future currency such ideas should have.

This idea could be developed in the area of church and state relations, which most of the authors touch on. Another area of interest here is the way in which state regulation impacts on churches even when they are not the primary objects of such regulation. The authors offer a range of perspectives. The Pentecostalist account suggests that they find the structures offered by secular charity law a welcome model to use to structure their own internal bodies; this can be juxtaposed to the scepticism about the effect of these laws seen from a Baptist perspective by Paul Goodliff. In this latter case Goodliff's views seem to come not merely from anxiety about the way in which the regulatory burden of the modern state make the existence of small independent congregations ever more precarious and challenging (though indeed this is a good point) but from a wider sense of Baptist identity as a tradition that has experienced more state persecution than most at almost every stage of its existence from seventeenth-century England to twentieth- century Russia.

The authors all then go on to examine how the Principles fit with the legal structures of their own respective traditions. This is not some exercise in bland ecumenism: most authors are happy to acknowledge such a fit, even when a certain amount of benign interpretation is needed to demonstrate that, but also to criticise the Statement when it does not seem to fit well. Three areas stand out in this. The first is the tendency of the Statement to suggest that churches ‘may’ regulate a particular matter (rather than ‘must’), which many feel is a not altogether satisfactory attempt to leave space for the reformation idea that church law is adiaphora. The second is the attempt to see legal structures existing at a national and international level, which for some of the reformed traditions appears to contradict the basic ecclesiological idea that the local church is the only theologically significant corporate body – here one may hope that not merely wider contacts within each tradition, but the ecumenical movement itself may lead to a more positive approach. Finally, there is the question whether authority in the church can be exercised by individuals or only by groups. Unsurprisingly, these are all vital questions in ecumenical theology – and church law offers a necessary space for them to be explored.

This volume offers a fascinating collection of essays, which should be required reading for all those interested in canon law, ecclesiology and ecumenism. It opens new horizons in all three disciplines and points to further fascinating conversations. Norman Doe is to be warmly thanked for his work.