Until the launch of this series over ten years ago, the 15,000 volumes of the ancient Greek commentators on Aristotle, written mainly between 200 and 600 AD, constituted the largest corpus of extant Greek philosophical writings not translated into English or other European languages. Over 30 volumes have now appeared in the series, which is planned in some 60 volumes altogether. This text by Philoponus, the sixth-century commentator on Aristotle, is notable for its very informative Introduction to Psychology, which tells us the views of Philoponus, of his teacher and of later Neoplatonists on...