Over 200 titles once attributed to the great philosopher Aristotle have been preserved in three ancient catalogues. Many commentators studied Aristotle’s work during Ancient and Middle Ages, some of which distorted his thought and added their comments. The first of them tried to bring out the differences between Plato and Aristotle, while later on there was an attempt by Porphyry to harmonize them. The most important commentators are Alexander of Aphrodisias, Ammonius, Themistius, Philoponus, Simplicius, Voetius, and mainly Thomas Aquinas. The first modern publication of Aristotle’s work is the five volumes of the Academy of Berlin by Bekker (1831-1870).