The heretofore unpublished Kitab al-Zina, virtually unknown in western scholarship, is a glossary of important Islamic terms by the 9th/10th-century Ismaili polymath Abu Hatim al-Razi. Some lament that Razi’s historical approach to etymology failed to catch on and that had it done so, the face of Arabic dictionary writing might have been altered for the better. His organization of material was uniquely Ismaili as he took pains to synthesize contradictory information into a harmonious whole. This study examines sections of Razi’s work with a view towards his contributions to the field of grammar and linguistics.