 There is no information concerning the impact of Alexander’s teaching in his lifetime. But certain indications of critical attacks on his contemporary Galen (129–216 CE) suggest that he was engaged in controversy with other contemporaries as well. Whether his polemics against contemporary versions of Stoic doctrine were part of a personal exchange or rather a bookish exercise is unclear. If Alexander held the chair of Peripatetic philosophy at Athens it is quite possible that he was in direct contact with the incumbents of the other philosophical chairs there. He was, of course, not the first commentator on Aristotle. But posterior exegetes certainly treated as exemplary his method and his standards for explaining problems and obscurities in Aristotle’s texts. This is indicated both by explicit references in later commentators and by the unacknowledged exploitation of his work in some extant later commentaries on the same texts. As the translations of his work into Arabic and, to a lesser degree, into Latin show, he continued to be treated as a leading authority and his work influenced the Aristotelian tradition throughout late antiquity, the Middle Ages, and in the Renaissance. Scholars nowadays continue to make use of his commentaries, not only for historical reasons but also because his suggestions are often worth considering in their own right. Because in recent years much more attention has been paid to the philosophers in late antiquity, not only to the Neo-Platonists, Alexander’s work has come under detailed scrutiny in various respects by specialists, as witnessed by an increase in publications both on general and on special aspects of his exegetical and philosophical work. The accessibility of most of his writings in English translations will make apparent to a more general readership that Alexander’s work is not only relevant for specialists in the history of philosophy, but opens up an interesting age of transition in the history of philosophical and scientific ideas.