Commentaries on Aristotle. Many years before Grosseteste composed his translations of the Nicomachean Ethics and De caelo, he had been deeply engaged in the study of Aristotle’s views on scientific knowledge and natural philosophy, and had composed a commentary on the Posterior Analytics and commenced and made substantial progress on a commentary on the Physics. These are the earliest surviving commentaries on these works known to have been composed in the Latin West.  Extant manuscripts also contain and attribute to Grosseteste a paraphrase of the Prior Analytics, which may well be genuine, as well as a commentary on the  Sophistici Elenchi and another commentary on the Physics, both of which appear to be inauthentic. The commentary on the Posterior Analytics appears to have been written in the 1220s and is an important source for Grosseteste’s epistemological views. The authentic commentary on the  Physics appears to have been assembled by a later editor or editors from notes Grosseteste had written in his copy of the Physics as the basis of a commentary along the lines of the commentary on the Posterior Analytics.  Though incomplete, these notes comprise a substantial and coherent work, the bulk of which was also probably written in the 1220s, though what appear to be some additions to the body of the work in which Averroes’s long commentary on the Physics is used probably date from the 1230s (see Lewis 2003).  This work is an important source for Grosseteste’s views on numerous topics in natural philosophy.