2016 marked the 800th anniversary of the foundation of the Dominican Order of Preachers, prompting a number of scholars to re-examine the Order’s origins. One of the aspects of early Dominican life that still merits further investigation is its chant and liturgy. Although various hypotheses have been proposed—that the Dominican liturgy is based on that of the Cistercians, or of Paris, for example—little progress has been made in untangling these propositions and understanding the processes behind the establishment of the Dominican liturgy. Only a handful of books survive from the early years of the Order, before the completion of a liturgical reform in the mid thirteenth century. Focussing on books for Mass, this paper will examine the early development of the Dominican liturgy and explore how their books were revised and updated, thus offering fresh perspectives on Dominican values in the thirteenth century.