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 our psychological capacities and on mind-body relations. There is an unusual account of how reason can infer a universally valid conclusion from a single instance, and there are inherited views on the roles of intellect and perception in concept formation, and on the human ability to make reasoned decisions, celebrated by Aristotle, but here downgraded. Philoponus attacks Galen’s view that psychological capacities follow, or result from, bodily chemistry; they merely supervene on that and can be counteracted. He has benefited from Galen’s knowledge of the brain and nerves, but also propounds the Neoplatonist belief in tenuous bodies which after death support our irrational souls temporarily, or our reason eternally.