In the 12th century, a remarkable golden age of Aristotelianism originated from a circle of philosophers in Byzantium maintained by the Emperor‹s daughter Anna Komnene, who had been excluded from participation in political life. Eustratios of Nicaea and Michael of Ephesus worked together on a commentary on ‹Nikomachischen Ethik‹ (Nicomachean Ethics) which was commissioned by Anna. Eustratios wrote the commentary on Books I and VI, Michael of Ephesus on Books V, IX and X. Apart from that, there are several commentaries by Michael on Aristotle‹s natural philosophy, whereas here we have a reprint of Eustratios‹ commentary on Book II of the ‹Analytica posteriora‹. The Latin translation of the commentary on the ‹Posteriora‹ (together with a short anonymous explanation of the work) by Andrea Grazioli, a physician, ushered in a new era in the interpretation of the Aristotelian theory of science.