The Dominican liturgy was defined during the years 1254–6, under the mastership of Humbert de Romans, then confirmed by Clement iv in 1267. The Ecclesiasticum officium secundum Ordinem Fratrum Praedicatorum, the prototype manuscript of 502 leaves which preserves the complete liturgy of the order, was composed in Paris in 1256–9, and there it was kept, in the Couvent St Jacques, until the French Revolution; it is now in Rome, at Santa Sabina (Archivum sancti ordinis fratrum Praedicatorum). As Fr Pierre-Marie Gy (1922–2004) remarks in the preface to this volume, not many liturgical manuscripts can be as well placed at the centre of an interdisciplinary study as this one; indeed the manuscript was the centre of a colloquium held in 1995 in which the author of the present volume took part: ‘Liturgie, musique et culture au milieu du XIIIe siècle: autour du ms. Rome, Santa Sabina XIV L1, «prototype» de la liturgie dominicaine’: actes du colloque international organisé par la Biblioteca apostolica Vaticana, l'École française de Rome, l'Institut de recherche et d'histoire des textes (CNRS) et l'Istituto storico domenicano, Rome, 2–4 mars 1995 (to be published in the series Studi e Testi). This study begins with an overview of the Dominican liturgy, a very thorough historical and codicological description of the exemplar (Rome, ms S. Sabina xivl1), and an edition of the sanctoral of the lectionary. The second part of the volume includes the identification of the sources; a careful analysis of their use, and a comparison with two other lectionaries, that of the Cistercians and the one adopted by the papal chapel, showing that the points of contacts are after all limited. A first appendix describes the structure of the Dominican canonical office, and the office for Matins; the second contains excerpts from legislative sources pertaining to the sanctoral; the third is made up of many elaborate tables and graphs which offer immediate and precise visual evidence to illuminate various issues discussed in the book; the fourth offers a comparison between the lessons of the portable breviary and those of the lectionary. They are followed by very extensive and complete indexes. The publication of the author's thesis, completed in 1997, was delayed by her sudden death in 1998 and it has taken almost ten years to bring it to conclusion. Fortunately many will be able to benefit from this remarkable analysis of the Dominican sanctoral.