This is a supplement to Adam Gacek's catalogue of Arabic manuscripts in the Library of the Institute of Ismaili Studies. It includes 188 Arabic manuscripts not listed earlier by Gacek. The catalogue is arranged alphabetically by author and chronologically by title.

This bibliographic work is a supplement to Adam Gacek's two-volume catalogue of Arabic manuscripts in the library of the Institute of Ismaili Studies, published in London, 1984-85. The Supplementary Catalogue includes 188 Arabic manuscripts not listed earlier by Gacek or which have been acquired since then by the institute's library. The majority of the works belong to the theological, philosophical, and historical traditions of Fatimid Ismaili literature. The catalogue is arranged alphabetically by author and chronologically by title, accompanied by details about the content of each work and other relevant information of a literary, historical, and doctrinal nature.