The monk Rodulfus Glaber is best known for his Five Books of Histories, a major source for events in the first half of the eleventh century, and valuable above all for revealing the mental furniture of an eleventh-century monk - for his account of the millennium, of relics genuine and false,of church-building, and visions of saints and demons. This edition, the first since 1866, presents the only critical text of the Histories, accompanied by a complete translation and a full historical commentary. Glaber also wrote a Life of his mentor, St William of Dijon, the renowned monasticreformer. The Life is reprinted after the Histories, again with translation and notes. The evidence for Glaber's life, and the value of his work are discussed in a Historical Introduction.