Geoffrey of Aspall, who died in 1287 and was master of Arts by 1262, was active at Oxford in the years 1255 to1265. He wrote commentaries on several Aristotelian works, and was certainly a major protagonist of the introduction of Aristotelian learning to Oxford. In particular, he produced a very extensive question-style commentary on Aristotle's Physics, which contains important discussions of the fundamental topics of Aristotle's natural philosophy, like matter, form, natural agency, causes, change, the infinite and the continuum, time, the eternity of the world, self-movers. Aspall's Physics commentary shows the influence of Grosseteste's metaphysics of light and of Roger Bacon's view on the physical role of intentional species, as well as a strong inclination to ontological realism. Aspall's commentary on Aristotle's Physics is edited here in two volumes, which together form the first critical edition of this work. The Latin text is accompanied by a facing English translation, and the text is extensively cross-referenced and provided with scholarly apparatus. The detailed introduction guides the reader through the intricacies of the textual transmission of Aspall's commentary, and also presents the main topics discussed in this commentary. The appendix to the edition makes available alternative versions of some sections of Aspall's commentary. Introduction 1. Life and works of Geoffrey of Aspall 2. The Questions on the Physics 3. Manuscript tradition and editorial principles 4. Presentation of the text 5. The main doctrinal points of Geoffrey of Aspall's Questions on the Physics Bibliography QUAESTIONES SUPER PHYSICAM, LIBRI I-IV, VIII (Recensio O) Tabula quaestionum / List of questions LIBER I / BOOK I LIBER II / BOOK II LIBER IV / BOOK IV LIBER III / BOOK III LIBER VIII / BOOK VIII Cecilia Trifolgi: BA ('Laurea') in Philosophy (1986) and BA in Mathematics (1995) from the University of Pisa. PhD in Mathematics from the University of Milan (2001). Since October 1999, University lecturer in medieval philosophy at the University of Oxford, and since October 2008 Professor of Medieval Philosophy. Specializes in the reception of Aristotle's philosophy (especially natural philosophy and philosophy of mind) in the 13th and 14th centuries. Silvia Donati is a researcher at the Albertus Magnus Institut in Bonn. She works currently on the critical edition of Albert the Great's corpus on the Parva Naturalia. Her research focuses on the 13th and early 14th century reception on Aristotle's Libri naturales. Her most recent publications include: Tra psicologia e filosofia della natura: la teoria delle species nella discussione sulla causalita naturale (Commenti inglesi ai Libri naturales, 1240-1300 ca.), in DSTFM 26 (2015); Is Celestial Motion a Natural Motion? Averroes' Position and its Reception in the Thirteenth and Early Fourteenth Century Commentary Tradition of the Physics, in P. Bakker ed., Averroes' Natural Philosophy and its Reception in the Latin West (Leuven University Press 2015 E. Jennifer Ashworth read history at Girton College, Cambridge and then received a PhD in philosophy from Bryn Mawr College in the United States. Teaching career was spent in Canada, first at the University of Manitoba from 1964 to 1969, and then at the University of Waterloo in Ontario from 1969 to 2005. Specialized in late medieval and Renaissance logic and semantics.