Aristotle's Meteorology influenced generations of speculation about the earth sciences, ranging from atmospheric phenomena to earthquakes. The commentary of John Philoponus (6th century AD) on the opening three chapters of Meteorology is here translated for the first time into English by Dr Inna Kupreeva, building on the work of L.G. Westerink. Philoponus, who today is increasingly respected as a philosopher in his own right, here engages critically with Aristotle's views about the building-blocks of our world, its size and relationship to other heavenly bodies, and reception of warmth from the sun. The translation in this volume is accompanied by a detailed introduction, extensive commentary notes and a bibliography.