Giannozzo Manetti (1396-1459) was an Italian diplomat and a celebrated humanist orator and scholar of the early Renaissance. Son of a wealthy Florentine merchant, he turned away from a commercial career to take up scholarship under the guidance of the great civic humanist, Leonardo Bruni. Like Bruni he mastered both classical Latin and Greek, but, unusually, added to his linguistic armory a command of Biblical Hebrew as well. He used his knowledge of Hebrew to make a fresh translation of the Psalms into humanist Latin, a work that implicitly challenged the canonical Vulgate of St. Jerome. His Apologeticus (1455-59) in five books was a defense of the study of Hebrew and of the need for a new translation. As such, it constituted the most extensive treatise on the art of translation of the Renaissance. This ITRL edition contains the first complete translation of the work into English.