Professor Brugger engagingly begins this book by describing how research into what initially seemed a quiet backwater of historical theology became important for one of the hottest topics in contemporary theological discussion. Underlying a considerable number of approaches to the theology of marriage today are a number of suggestions, resting largely on the scholarship of Piet Fransen, that Trent did not really teach that marriage was indissoluble – and drawing from this the conclusion that the Church today has the theological space to revise its present teaching on this subject. In the light of these suggestions Brugger asks what Trent really did teach.

Before looking at what conclusions he reaches on this, it is worth noting how he gets there. The book offers an exemplary treatment of the historical path by which Trent arrived at its teaching on the marriage bond. Brugger looks at the various challenges that were being posed to Church teaching and practice on marriage, both from the Reformers and from the Orthodox (the ‘Greeks’, in the terminology of the time), and then traces the evolution of Trent's teaching from the first sessions which dealt with marriage in 1547 through to the final formulation of 1563 (one of the last great acts of the Council). This section of the book would be a fascinating read were it to stand alone – by looking at this small topic Brugger opens up an insight into the way the whole Council worked. His use both of the Acta and of the work of modern scholars (most notably Jedin) is synthesised to illustrate in microcosm the way in which bishops and theologians interacted at the Council, the influence of the Council's leading figures, and the way in which it reacted to developing events outside (most notably, the Cardinal of Lorraine's response to Calvin's teaching on marriage). Appendices offer a detailed account of the voting and speaking records of the bishops, and a helpful collection of texts (with translations) which the Council relied on as authorities.

The strand of scholarship notably asserted today by Fransen, but which goes back to Paolo Sarpi, that Trent was really teaching about the authority of the Church to legislate about marriage, not about marriage in itself, is put to flight by Brugger. Careful comparison which the marriage canons which are disciplinary, reflection on the language of the bishops during the debates, and exact analysis of the text of Trent's canon 7 show that considered both in letter and intention it affirms a dogmatic definition of absolute indissolubility as a divinely revealed truth. His careful analysis enables one to go further, and avoid an over‐simplistic statement of its intentions. Canon 7 is carefully framed so as not to anathematise the Greeks notwithstanding their error about the nature of marriage (while at the same time clearly including Luther's teaching within an anathema). The Council of Trent is shown to have recognised and wished to preserve the real but imperfect communion that existed with the Orthodox in this area – a more general examination of ecumenical sensitivity at Trent would surely be a worthy future subject of study.

This book has much to offer scholars of the history of theology, but it would be a shame if its readership were confined to those whose interest is primarily historical (fascinating though they will find it). Despite the apparent narrowness of the title, this book is one that will be indispensable for those wishing to reflect on how to present the Church's teaching on marriage today in a way that remains faithful to its tradition.