This volume contains five Latin versions of Aristotle's Categories. Numbers 1 and 2 both stem from Boethius, who is responsible for the Latin translations that were most widespread. One of them is more literal, the other more elegant. William of Moerbeke, on the other hand, was the author of a Latin version not only of Aristotle's work (3), but also of Simplicius' commentary, which contains the abbreviated lemmas of the Aristotelian text (4). Moreover, Aristotle's work was known by means of a Roman paraphrase attributed to Augustin and influenced by Themistius (5).