The no longer extant commentary by Alexander of Aphrodisias (approx. 200 AD) on Aristotle's Physics is one of the most important works of antiquity ‑, as a source text having influenced both the Greek commentators on Aristotle and ‒ through the mediation of Arab scholars ‑ Western medieval philosophy. This volume presents the first edition and study of nearly 700 recently discovered Byzantine scholia, which allow a more exact reconstruction of Alexander's teachings on physics, and at the same time contribute to a better understanding of Aristotelianism and preclassical physics.