This volume aims to reconstruct John Philoponuss (6th century CE) lost commentary on the third book of On the soul (De anima), in which Aristotle discusses crucial arguments in his doctrine of the intellect. The first part of the volume presents theeditio princepsof numerous Greek scholia deriving from Philoponuss commentary. The second part provides a complete retroversion into Greek of sections 4-8 of De animaIII, which were preserved in a Latin translation by William of Moerbeke (13th century), while the third part offers a revised edition of relevant passages from the paraphrase ofDe animaby the Byzantine scholar Sophonias (13th century), who used Philoponus's commentary as a primary source.