This book contains the first English translation of an important medieval treatise on Aristotle'sMetaphysics. The original Arabic text was composed around 1160 by the famous Andalusian philosopher Averroes (Ibn Rushd). The present translation has been prepared on the basis of a wide range of documents including, apart from the available Arabic editions, various medieval manuscripts as well as a Latin translation prepared in the Renaissance. It is accompanied by a commentary dealing with the major philosophical topics and philological problems of the text.