The first chapter of Professor Müller's book contains a nice piece of archival detective work. Starting with a cryptic account of the receipts of the keeper of the seal of the archdeacon of Xanten (on the Lower Rhine) for the year 1516–1517 and an equally cryptic and incomplete register of cases heard before the official of the same archdeacon, Müller, on the basis of a few entries that coincide, reconstructs what most “cases” were probably like in this court (32–42). Müller then goes down the Rhine to Basel, and to another group of records, where he finds the same pattern of cases in sufficient quantity that he can count them. This pattern then is converted into the hypothetical case of Michael and Mary that appears in the introduction (1–3). The couple are cited ex officio before an ecclesiastical judge on the basis of local reports that they were committing fornication. Mary swears that they are married. (He promised to marry me and then had intercourse with me.) Michael admits the intercourse but denies the promise. Mary has no proof of the promise, or, at least, not sufficient proof. Michael is ordered to do public penance for the fornication. Mary is not, but she may not in conscience marry another since she has sworn that she is married to Michael. She may, however, at least in some places, recover damages for defloration, and child support if her relationship with Michael resulted in a child.

The first of Müller's main theses in this book is that the overwhelming majority of medieval marriage cases in Northern Europe (England, Northern French-speaking areas, and Germany) were of this type, actions to enforce a marriage, not to obtain an annulment or a separation. He does not seem to be claiming—nor could he claim—that the overwhelming majority were of the type of the modal case that is featured in the Introduction. His claim, however, is that the overwhelming majority of marriage-enforcement cases in this geographical area were “penitential” not “judicial.” By “judicial” he seems to mean following the long-form ordo iudiciarius, including the introduction of witnesses and/or written documents. His “penitential” cases lack these elements of the ordo but are not necessarily ex officio (brought nominally in the name of the judge against alleged offenders of church law). The high annual volume of cases found in Paris (1384–1387), Augsburg (1348–1352), and Regensburg (selected years from 1489 to 1515) all seem to have been instance cases (brought by a private party). The seeming dominance of the “judicial” in England is explained by an assertion that is not well supported at this level of generality that lesser ecclesiastical courts handled a large volume of cases similar to those found in the surviving records of the “Franco-German” courts.

The second main thesis is that marriage-enforcement cases are relatively infrequent in the records in Southern Europe. (Müller deals with Spain and Italy with some reference to the work of others on Southern France.) Much of the three chapters on Southern Europe is spent documenting that this is, in fact, the case, and showing what other kinds of marriage cases are found in this region. Müller's tentative explanation for the relative lack of marriage-enforcement cases is that people in this region found ways to resolve such disputes that did not involve the ecclesiastical courts or that such disputes were relatively infrequent because of the notarial tradition in the area.

An Appendix to the book (218–245) contains statistics about marriage cases in eight diocesan court registers. A large amount of work was involved in compiling these statistics, and they advance our understanding of marriage litigation in the Middle Ages considerably. They should, however, be used with caution. To take but one example, the Ely case called “Dalling/Savage” (no. 88) is classified as a simple contested enforcement action that the woman asserting the existence of the marriage lost (241). Later on the same page, the same case is classified as a double contested enforcement action that both women asserting the existence of the marriage lost. It is, in fact, a triple contested enforcement action that one of the women asserting the existence of the marriage won, and the other two necessarily lost (Ely Register, entry 34.12; entry 44.22).

The Bibliography (246–263) is comprehensive and includes everything cited in book. Absent is Beatrice Gottlieb's 1974 Columbia Ph.D. dissertation. Had Müller had it, he would have been able to expand his survey of the Northern French registers to include those of Troyes and Châlons-en-Champagne. Also absent is the 2014 volume of conference papers: Les officialités dans l'Europe médiévale et moderne. Had Müller had it, he might have modified some of his conclusions about both France and Spain.

There is much in this book that is valuable and interesting. It is regrettable that Müller chose to devote—or his publisher insisted that he devote—only 216 pages of text to a topic that calls for more discussion of its variety and nuance. That Müller is aware of this variety and nuance is indicated by a number of remarks that he makes in passing in the text, and, in one case, by an entire chapter (ch. 6, “Domestic Partnerships in Iberia”). This awareness, however, did not get translated into the bold generalizations, particularly the one about Northern Europe, that are a principal feature of the book.