Ranulph Higden, O.S.B. (ca. 1285-1364), well-known author of the Polychronicon , also penned several pastorally oriented treaties, namely, an Ars componendi sermones , a lengthy series of Distinctiones , an Ars Kalendarii , and a comprehensive manual of instruction called Speculum Curatorum . Last revised about 1350, the Speculum handles almost every aspect of Christian doctrine in three substantial books: the first treats the commandments; the second, the deadly sins; the third, the sacraments. This edition and translation of Higden's volume on the Decalogue shows how each commandment functions as an umbrella covering various expected and unexpected subjects. Because of the former, it is a serious explication of moral theology and canon law; because of the latter, it is a treasure trove of myth, folklore, vignettes detailing aspects of fourteenth-century life, and avuncular advice. Its definitions of intangibles - like faith, fear, and flattery - are balanced by evaluations of war, robbery, and tithing, and given zest by discussions about the degrees of superstition, the tricks of demons, and the deceitfulness of dreams. Ultimately, all provide insights into the knowledge base, the legitimate and unfounded concerns, and the sincere beliefs of later medieval England.