Bar Hebraeus, a celebrated polymath and writer of thirteenth century Syria, wrote on nearly every subject imaginable. The Book of Ethics is a Syriac manual of discipline and etiquette covering secular life as well as spiritual life. Composed as four treatises, the book addresses the obligations of prayer and forms of behavior advocated by the Bible and the Egyptian desert fathers. The first and second books concern training and maintaining the body. The third book focuses on purifying the soul. By far the longest treatise is the fourth, a book that instructs the reader how to adorn the soul with virtues. A fascinating view into the world of an early attempt at clarifying ethical behavior, this resource in Syriac contains much that will be of interest to ethicists today.