During a period of over five years of work in the Biblioteca Ambrosiana in Milan, the author has examined the majority of its Arabic manuscripts in order to provide some elementary codicological data. This monograph describes the Kitāb Ġurar al-fawāyd by aš-Šarīf al-Murtaḍā contained in manuscript MS.1665 (H 43) and other copies of the same text preserved in some Western European libraries, with regard to their historical, linguistic, artistic and bibliographic aspects.