"One of his six introductions to philosophy, widely used by students in Alexandria, Ammonius' lecture on Porphyry was recorded in writing by his students in the commentary translated here. Along with five other types of introductions (three of which are translated in the Ancient Commentators on Aristotle volume Elias and David: Introductions to Philosophy with Olympiodorus: Introduction to Logic) it made Greek philosophy more accessible to other cultures. These introductions became standard in Ammonius' school and included a popular set of five or more definitions of philosophy, some of them drawn from commentaries on quite different works."