 Among his other works, Tûsî wrote the Book of Abstraction as a non-polemical exposition of logic. His famous and influential student, al-‘Allâma al-Hillî (d. 1325), who had also studied under Kâtibî, wrote a commentary on it, the Facetted Jewel on the Book of Abstraction (Hillî 1363 SH). It is only relatively recently (the late nineteenth century) that the text and commentary were printed and came to be used in Shî‘î seminaries to introduce logic (El-Rouayheb 2010b: 108 n77). On the face of it, the text is quite conservatively Aristotelian, its rubrics following the traditional course of topics covered in the Organon, and in the same order; for all that, the substantive doctrine seems on the whole to be pristine Avicennan, precisely the doctrine Tûsî defended against Râzî, Khûnajî, Abharî and Kâtibî.