In this study of the rare twelfth-century treatise On Diverse Arts, Heidi C. Gearhart explores the unique system of values that guided artists of the High Middle Ages as they created their works.

Written in northern Germany by a monk known only by the pseudonym Theophilus, On Diverse Arts is the only known complete tract on art to survive from the period. It contains three books, each with a richly religious prologue, describing the arts of painting, glass, and metalwork. Gearhart places this one-of-a-kind treatise in context alongside works by other monastic and...