Abū al-Ḥajjāj Yūsuf b. Muḥammad Ibn Ṭumlūs (Alhagiag Bin Thalmus, d. 620/1223) was a philosopher, physician and direct disciple of Ibn Rushd (Averroes, d. 595/1198), who lived and practiced rational sciences in Alzira and Marrakesh, a quarter of a century after the demise of his teacher. Ibn Ṭumlūs was not Ibn Rushd's only student who engaged in work on logic, but one of dozens of disciples, suggesting that the supposed simultaneous death of the latter’s philosophy is “grossly exaggerated”. As a valuable window into the practice of logic in 13th century al-Andalus and the Maghreb, Ibn Ṭumlūs' Compendium on Logic (Al-Mukhtaṣar fī al-manṭiq) covers all the parts of “the expanded Organon”, as it was known since al-Fārābī (d. 339/951). The present volume offers a complete critical Arabic edition of this work, with an English and Arabic introduction, notes and indices.