Porphyry (AD 232/3 - C.305) is of crucial importance for the history of Aristotelian studies. Born in Tyre and a student of Plotinus in Rome, he later defended Aristotle's Categories against Plotinus, arguing that they were entirely compatible with Platonism. His intervention was decisive: the Categories became a basic textbook of logic for all subsequent Neoplatonist teaching and influenced both the Arabic and Western Traditions. Boethius drew heavily on Porphyry's treatment. The full commentary is lost, but a shorter version survives and is translated here.

Preface
Introduction
Textual Emendations
TRANSLATION
Notes
Bibliography English-Greek
Glossary Greek-English Index
Index of Passages Cited
Subject
Index