Aristotle''s theory of eternal continuous motion and his argument from everlasting change and motion to the existence of an unmoved primary cause of motion, provided in book VIII of his Physics, is one of the most influential and persistent doctrines of ancient Greek philosophy. Nevertheless, the exact wording of Aristotle''s discourse is doubtful and contentious at many places. The present critical edition of Ishaq ibn Hunayn''s Arabic translation (9th c.) is supposed to replace the faulty edition by A. Badawi and aims at contributing to the clarification of these textual difficulties by means of a detailed collation of the Arabic text with the most important Greek manuscripts, supported by comprehensive Greek and Arabic glossaries.