In early eleventh century Zaragoza, the eminent Jewish scholar Abu l-Walid Marwan ibn Janah wrote a glossary containing almost 1100 entries, entitled Kitab al-Talkhis. This important text, considered lost until recently, contains Arabic and foreign-language names of simple drugs, weights, measures, and other medical terms. In the present volume, the Kitab al-Talkhis is edited and translated for the first time by Gerrit Bos and Fabian Kas. In detailed commentaries, the editors identify the substances mentioned in the Talkhis. They also elaborate on the role of the text in the history of Arabic glossaries concerned with medical nomenclature. Special attention is paid to Ibn Janah’s Ibero-Romance phytonyms, analysed in depth by Mailyn Lubke and Guido Mensching.