This is a prodigious and thorough study of liturgy in medieval England based on a lifetime's experience with the sources, the surviving liturgical manuscripts and printed books, and on a masterful summary of the scholarship of the last two centuries. With a careful historian's eye, Richard Pfaff gives an account of the origins, development and florescence of the English mass and office, beginning with an examination of the evidence for ‘partly traceable’ early Anglo-Saxon forms. He accounts for the effects of the Norman Conquest and the development of Benedictine and other monastic and religious patterns in their insular context. Thorough, too, is his treatment of the several patterns that existed in the secular liturgy of cathedral and parish church. Richard Pfaff gives attention not only to the influence of named individuals within the ecclesiastical hierarchy but also to the details of individual witnesses framed within the balance of evidence, a feature that should be of considerable use to scholars investigating a particular manuscript. Most interesting, and perhaps most valuable, are the five ‘excursus’, each of which treats a methodological concept or problem: interpreting the sources; unpacking the labels ‘Gregorian’ and ‘Gelasian’; comparing liturgical texts; assigning books to places of use; and the available evidence for female religious houses. These sections offer much-valued insight into the thought processes and reasoning of the author. There are few criticisms that can be made of such a well-researched and carefully written work. But in a single volume, even one of this size, there must be inevitable omissions. Episcopal and occasional services that fall outside mass and office do not appear; similarly, the musical material has not been discussed. The preface readily acknowledges these shortcomings. As a whole, Pfaff's text seems to be constructed with each chapter as a self-contained narrative. Consequently the volume as a whole can seem rather episodic. This, too, is deliberate. In spite of the chronological ordering of sections the self-contained chapters help to challenge the conventional, teleological belief in the linear development of liturgical patterns that has so often prejudiced liturgical research. In his own words, Pfaff here supplies ‘a, with no pretence to being the definitive, history of the subject’. The liturgy in medieval England is the crowning achievement of a long and influential career. It will undoubtedly serve as a crucial reference work for all for whom the medieval English liturgy has relevance.