Rodriquez-Arribas's presentation examines the genre of the instrument book in medieval Hebrew and, specifically, it focuses on the first treatises written in Hebrew describing and explaining the astrolabe. As far as is known, Abraham ibn Ezra (1089/92-1164/67) was the first Hebrew writer to deal with this subject and implement the language of the Bible and the rabbis for conveying and explaining the parts and uses of this scientific instrument (until then described in Greek, Syriac, Arabic, and partly in Latin, but never in Hebrew). It is indisputable that Ibn Ezra's treatises are the context in which many new meanings and words were coined in the field of scientific instruments and astronomy, and they are among the first texts to make Hebrew a language capable of scientific expression (and eventually, research). The paper also takes into consideration the only extant Latin treatise that Ibn Ezra wrote on the astrolabe, as well as the Jewish communities intended for everyone of the texts.