At long last a comprehensive tool in English for a better understanding of the most basic terms in Aristotle's philosophy. Interested readers, students and scholars of philosophy and of the general intellectual background of Western culture need no longer be handicapped by a lack of knowledge of Greek and Latin. A careful comparison of the original Greek, medieval and Renaissance Latin translations and a reappraisal of English usage make this work a definitive source for the precise grasp of what has been the historical Aristotle as far as the documents permit one to judge.