This fifth volume of the Mediaeval Continuation is the fourth of the letters of Peter Damian, an 11th-century monk and man of letters. Written during the years 1062-1066, these letters deal with a wide variety of subjects. Some letters are of historical interest, others approach the size and scope of philosophical or theological treatises. Damian's correspondents range from simple hermits in his community to abbots, bishops, cardinals and even to Pope Alexander II. Among these letters are to be found one addressed to the patriarch of Constantinople, two to Damian's sisters, one to the Empress Agnes, and even a few to such distant personages as the young King Henry IV and the Archbishop Anno of Cologne. Like its companions, this volume uses Damian's thought to understand an important period in the history of church and state. Clearly, the most significant letter in this collection is Letter 119, written in 1063 to Abbot Desiderius of Monte Cassino and his monks, on the omnipotence of God. Damian's treatise on "Divine Omnipotence" demonstrates his control of both theological and philosophical methodology. His opponents are contemporary rhetoricians whose denial of God's total potency in dealing with his creatures' contingencies in time past, present and future opens them to the charge of heresy.