Richard Rufus of Cornwall was an early Scholastic philosopher-theologian who taught at the Universities of Paris and Oxford between 1231 and 1255. In those years he played a vital part in the transformation of philosophy and theology in early thirteenth-century Western Europe. He pioneered theteaching of metaphysics, physics, chemistry, psychology, and ethics. At Paris Rufus gave the earliest lectures on Aristotelian physics and metaphysics of which a record survives. Although acknowledged as a great scholar in his lifetime, his devotion to the Franciscan ideal of humility led himdeliberately to seek obscurity and for 500 years his work was lost or misattributed. This is the second volume of Richard Rufus's writings in the Auctores Britannici Medii Aevi series, a companion to In Physicam Aristotelis also edited by Professor Rega Wood.De Generatione et corruptione is particularly notable for its accounts of divisibility, growth and Aristotelian mixture. This transforms our understanding of the introduction of Aristotelian natural philosophy to the West and provides insight into the early history and prehistory ofchemistry.