The Dominican Order is said to be famous in modern scholarship for its remarkable organisational structure. But, asks the editor early on, what happened when the rules were broken, or when there simply were no rules or only insufficient or incongruous ones to follow? This volume is an original and substantial scholarly exploration of these issues, although the subtitle could mislead as in fact only the medieval period is covered. J.G.G. Jakobsen's focus is on the Province of Dacia, and he makes the general point that one way to respond to rules is to follow them. Obedience tends to leave little evidence in the written sources. One should add, however, that there are the lives of Dominican saints, whose canonisation proceedings in the broad sense are among the documentary sources. Such Dominicans were by definition exceptional, yet the sources may also indicate what was considered normal and expected.

The fine chapter by Gert Melville, who coined and redeploys the illuminating term ‘system rationality’, is cast in terms of ‘The Fixed and the Fluid’. It is an introduction to the growth and development of Dominican legislative structures, to be read together with the editor's overview. The volume as a whole might have given more prominence to the universal canon law of the Church, in relation to which the proper law of the Dominicans and other religious operated. Dom Jacques Hourlier's comprehensive canonical coverage in L'Age Classique (1140‐1378): Les Religieux (1974) would make for a number of comparisons and contrasts. Indeed, recalling Melville's statement about the fixed and the fluid, there is a striking similarity to Hourlier's concluding assessment of the law concerning religious; it was ‘at the same time imperative and flexible, or rigid and free’. S. Steckel's chapter on a phase of the secular‐mendicant controversy in France, for example, shows the value of indicating general canonical material. Extensive use has been made, however, of the Acts of General Chapters, a pivotal internal juridical mechanism. The printing of the Constitutions for the first time (1505) made possible greater textual uniformity and was an opportunity, grasped energetically by the then Master General of the Order, Vincent Bandello, to inculcate their meticulous observance. What a full legal history of the Dominicans might contain, admittedly a distant prospect, can be gathered in part from Les Dominicains et leur droit (1999) and, of course, from the volume reviewed here.

The volume has 18 chapters divided into 3 Parts: Discussion, Implementation and Consequences. Part I is given over to the different modes of deliberation, exploring how medieval Dominicans debated, reflected upon and conceived of their legislation. The chapter on Dominican reform and heretical inversion in the fifteenth‐century Low Countries (M. Champion) can be related to that on heresy, inquisition and obedience by C.C. Ames. Ames asks how disciplining an inquisitor might become impeding him, so raising the need to coordinate different claims to the obedience of an individual friar. There is a reappraisal of the Barcelona public disputation of 1263, between a Dominican friar and a leading Jewish rabbi (H.J. Hames). In addition to the already mentioned chapters by Melville and Steckel, C.T. Leitmeir writes on Dominicans and polyphony, beginning with the seeming paradox that although the early friars have too often been portrayed as opponents of polyphony, the surviving musical sources suggest the opposite. The textbook Tractatus de musica by Jerome of Moravia OP (possibly of Moray in Scotland) incorporated cutting‐edge polyphonic practices, and Leitmeir goes as far as to conclude from thirteenth‐century Dominican codices that these friars cherished polyphony more than any other monastic order.

This perhaps unexpected chapter on polyphony is a kind of prelude to a good deal of the contents of Part II. There we have chapters on uniformity in the Dominican liturgy (E. Giraud, examining MS Oxford, Blackfriars 1 amongst others), and Dominicans (dis)obeying the regulations for the copying of chant books (H. Beban). S. Mickisch on architecture and space encapsulates a good deal, while M.P. Vidal's chapter on legislation, architecture and liturgy in the Dominican nunneries in Castile complements that of G.C. Moiteiro on a normative system for the observant Dominican nuns in Portugal. Proposing a fresh examination, J. Rubin considers the beginnings of the study of foreign languages, providing a needed focus on the Province of the Holy Land. Incidentally, could David of Ashby OP, who lived so long among the Mongols, have been of the English Province? A. Holloway looks at the central mission of preaching in terms of ‘performance management’, that is the management of what was preached and the performance of the preacher.

Two outstanding chapters, together with two fine studies focussed on Dacia, make‐up Part III. The latter pair deal respectively with Dominican implementation, observation and violation of rules in the Province of Dacia (J.G.G. Jakobsen), and petitions from Scandinavian Dominicans to the Apostolic Penitentiary in Rome (K. Salonen). Wolfram Hoyer OP is the only friar among the contributors, illustrating how widespread is the interest in Dominican history amongst scholars. Hoyer's overview of detention and imprisonment in medieval Dominican legislation is pioneering. It asks two searching questions: what crimes were punished by imprisonment? What regulations guided the practical application of this punishment? The answer to the first question results in no less than 10 categories. C. Linde also breaks much new ground in examining disciplinary deportations, that is, forced resettlement as a means of control and correction. She opens with the famous sentencing in 1261 of Simon of Hinton OP, prior provincial of England, discharged from office and assigned to the Province of Teutonia.

More than once, something will feature in different contexts. As with dispensation, a pronounced characteristic of the Order, or with the ‘chapter of faults’ so important for discipline and conventual architecture, or the case of Arnaldus de Prato, lector at Toulouse. He interests Linde because his sentencing at the 1294 General Chapter was deferred due to his absence. That Arnaldus was accused of having composed disrespectful songs about Dominican cardinals also draws the attention of Leitmeir in his chapter on polyphony. This volume is an academic achievement and a quarry of interesting facts.