At first sight, the juxtaposition of ‘peacemaking’ and ‘canon law’ seems unusual to say the least. However, Reid gives a unique insight into combining these two elements in his book. The work is divided into ‘parts’ rather than chapters. In Part 1, acknowledging that there are many different understandings of peace, for the purposes of the book, he begins by defining it as the absence of conflict. From this, he develops three strands. The first is a consideration of the role that the papacy can play in negotiating an end to international disputes. Contentious litigation is the second, with canon lawyers being at the forefront of developing rules to adjudicate trials and appeals. A third strand is alternative dispute resolution, where justice is achieved without the cost of litigation. Noting that the historical concept of the work is deliberately wide-ranging, Reid nevertheless suggests that it corresponds to three distinct jurisprudential ‘moments’ within the history of the Catholic Church. The first harks back to when the popes themselves were influential players on the international scene, themselves being the temporal rulers of the Papal States. The second ‘moment’ corresponds to the consolidation of centralised and absolutist power, characterised by the decree of papal infallibility during the First Vatican Council (1869–1870), and the promulgation of the Code of Canon Law in 1917. The third moment is that of the Second Vatican Council (1962–1965) during which the hope was given, and expectations raised, of a more participatory church.

Part 2 begins with the twelfth century when the papacy evolved into a great administrative and bureaucratic institution. Ranging through the growth of high papal ideology, the Great Western Schism, and an evaluation of the significance of Pope Martin V’s negotiations during the Hundred Years War, Reid concludes this part with an evaluation of arbitration as a means of resolving conflict in the Middle Ages, and notes the provision made by canon law for arbitration. Interestingly enough, the role of who may serve as an arbiter and whether this might involved lay people, whether men or women, is something that is still of relevance today in terms of cooperation in the power of jurisdiction.

Modern diplomacy forms the discussion of Part 3, beginning with the collapse of the Papal States in 1870. This year was also significant for its promulgation of the decree, Pastor Aeternus, which stated that papal decrees pronounced ex cathedra should be considered the infallible teaching of the Catholic Church and binding for all time. (It is worth mentioning here that this decree has been used only very seldom since that time, and in consultation with bishops worldwide before any definitive proclamation was made.) With the loss of the Papal States and the death of Pius IX, it might have been supposed that the Church would lose its influence in international affairs, and the appointment of Leo XIII brought a new impetus to the Church becoming the voice of conscience in the modern world. Indeed, students of Catholic Social Teaching are aware of the profound influence of Leo’s famous encyclical, Rerum Novarum (1891), on social matters (and which was the first document of many pontiffs since then which comprised a body of teaching on social matters which have had significant international influence), although Leo attempted to restore the Holy See as a serious participant in international affairs. Reid looks at one aspect of his effort in respect of certain territories (Spain, Germany, and the Caroline Islands). He notes that Leo was not just about acting in disputes but in giving his actions a theological grounding in his encyclical, Diuturnum (1881). Interestingly (and perhaps reassuringly) for secular powers, while the exercise of political power must conform to Christian principles, this did not mean direct subjection of states to papal authority, but that as part of the divine order, they enjoyed an appropriate autonomy in the larger social order. The remainder of this part looks at diplomatic efforts of popes since then, with a particular focus on John Paul II and Francis. Reid notes that John Paul II involved himself in a number of major diplomatic efforts, and looks at two of these, the dispute between Chile and Argentina, and his unsuccessful attempt to prevent the United States going to war against Iraq. Rather surprisingly (and unexplained) is that there is no mention of John Paul’s involvement with Poland and his contribution towards the fall of Communism. That could at least have merited a footnote, if not a mention. Francis’s efforts at peacemaking are compared with those of Leo XIII and John Paul II, noting Francis’s unconventional approach which is characterised by comprehensiveness, tenacity, and inventiveness. This may be a less-than-fair comparison, which could have been analysed further, particularly in relation to John Paul II and his contribution in hastening the changes behind the Iron Curtain.

Parts 4 and 5 consider the 1917 and 1983 Codes of Canon Law, respectively, with a shift to looking at mediation between private parties. An examination is made of various relevant canons, the role of judges, and the significance of alternative dispute resolution. The influence of the Second Vatican Council on the revised Code of 1983 is discussed, setting it against the backdrop of historical changes and what Reid terms the theological transformation of the twentieth century, and also the report of the Canon Law Society of America. Several relevant canons on arbitration and dispute resolution are discussed in depth, and these are worthy of further reflection by scholars, particularly considering the conflict engendered by the child abuse crisis, and further litigation on the horizon by claimants of spiritual and emotional abuse within the Church itself.

The Appendix gives a number of case studies which illustrate examples of possible litigation and arbitration. Although more relevant for North America, they provide a basis for examination in other civil jurisdictions.

Overall, this is a dense, well-researched book, with excellent footnotes and a comprehensive bibliography. If there is one criticism that might be made, it is that it might have made it easier for the reader had the material been separated into chapters with clearer introductions and conclusions. Nevertheless, this does not detract from the fact that this book is a good read, informative and thought-provoking.