 Psychology was another area in which Vives enjoyed considerable success. Philip Melanchthon (1497–1560) recommended De anima et vita in the prefatory letter to his Commentarius de anima (Commentary on the Soul, 1540). Vives’ influence on the naturalistic pedagogy of the Spaniard Juan Huarte de San Juan (c.1529–1588), in his celebrated El examen de ingenios para las ciencias (The Examination of Men’s Wits, 1575), is undeniable. In his discussion of the passions of the soul, the Jesuit Francisco Suárez (1548–1617) counted Vives among his authorities, pointing out that the study of the emotions belongs to natural philosophy and medicine as well as to moral philosophy. Vives’ treatise was also an important source of inspiration for Robert Burton (1577–1640), who, in The Anatomy of Melancholy (1621), repeatedly quotes from De anima et vita. The reference to Vives by René Descartes (1596–1650) in Les Passions de l’âme (1649) suggests that he had read the book.