With its profound insights, over three hundred chapters and more than four thousand scripture references in its eight books the Rationale Divinorum Officiorum (Rationale for the Divine Offices) stands in a class of its own. Written towards the end of the thirteenth century, the original, which was published in Latin, is the inspired opus of William Durandus, a highly regarded bishop of the time. Now, after more than seven centuries, it is possible for the English reader to discover the entire work of eight books along with an extensive index in seven volumes. However this work should not be regarded as a historical relic as the Ecclesiastical Offices have seen little change and most importantly, the spiritual foundations on which they rest are immutable. Furthermore, this work remains a primary authority on Western liturgies. Volume One of this translation contains the Author's Preface and Book One of this work. In his Preface Durandus points to the importance of the clergy having a sound understanding of the Offices and explains the various levels of spiritual interpretation the work presents. In Book One his focus is on the symbolic meaning of the church building and its parts. Here he examines not only the building but also at its contents and then cemeteries and other sacred and religious places. Durandus then moves on to examine the dedication of both church and altar. He concludes with a general consideration of the nature of the sacraments. The translator of this work, Janet Gentles, has spent over forty years exploring the spiritual foundations of both Christianity and Judaism as both assist in gaining an understanding of the profound teachings of the Bible. Her publication the Rationale Divinorum Officiorum, provides a substantial contribution to such understanding.