Volume Four of this translation of the Rationale Divinorum Officiorum contains Book Five of this work. This book examines the Canonical Hours observed within monastic communities. The monastic way of life is a very ancient form of Christian observance. Those who follow this way seek to remove themselves from the mundane way of life in order to commit themselves more fully to God. This includes observing regular hours of prayer, both of the day and the night, which are known as the Canonical Hours. In this book Durandus presents readers with an understanding of these regular times of prayer and their spiritual foundation. In doing so he continues to add to the understanding of those who seek a better spiritual perception of the Christian spiritual way. 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. The Rationale Divinorum Officiorum provides a substantial contribution to such understanding.