Treatise on the Love of God is in every respect a great work. Because of the book's order, clarity and sound doctrine, and because of St. Francis de Sales' vast knowledge and mastery of language, the work is an acknowledged classic. Excellently versed in both the Fathers and the Scholastics-especially St. Thomas Aquinas-St. Francis de Sales also shows his intimate knowledge of Sacred Scripture, startling the reader with surprising insights into its hidden spiritual meanings. A learned man in a learned era, St. Francis de Sales was moreover widely read in the Greek and Latin classics. The Treatise on the Love of God has well been called "the greatest work of genius in theology since St. Thomas, and one of the most learned." After laying the Scholastic groundwork (Book 1 of the Treatise), St. Francis de Sales launches into a masterful combination of theological principles and practical application regarding divine love-which is the subject of Our Lord's First and greatest Commandment. Going right to the heart of true religion, he shows how everything in the Catholic Faith hinges on this holy love and its growth in the soul. And in harmony with all Catholic teaching, he affirms that human actions are worthless when done without divine love (i.e., not in the state of Sanctifying Grace). Treatise on the Love of God brings the reader a giant step forward toward learning the great science of the Saints-the practice of the love of God.