Guigo II the Chartusian (1114 - c. 1193) was the ninth prior of the Grande Chartreuse. His Ladder of Monks is one of the great spiritual classics that has inspired the method of lectio divina -spiritual reading of the Holy Scriptures- since the early Middle Ages. We find its influence, for example, in the reflection of Saint John of the Cross on lectio divina -see: "When God Speaks: Lectio Divina in Saint John of the Cross," and it provides the key to understanding William of Saint-Thierry's "On Contemplation."