Just out, Thomas Aquinas' commentary on Aristotle's Perihermenias (also known as De Intepretatione). the commentary was probably written between 1269 and 1271, following his other 'Aristotelian' commentaries such as on the Posterior Analytics and on the Metaphysics. There are some notes on the Perihermenias, together with links to other commentaries (including this one) here.
I see Charles Freeman has just commented on an earlier post - welcome Charles. There were dozens, if not hundreds of medieval commentaries on this logical work by Aristotle. Many of them were written before the thirteenth century - Abelard's being the most notable of those.