The article focuses on the manuscript collection assembled by Karaite scholar Abraham Firkovich (1787-1874) during his travels in the Middle East. The collection comprises many texts that belong to important intellectual traditions of this region. The author emphasizes the importance of Firkovich's so-called Second Collection for the study of the medieval Arab-Islamic philosophical traditions. Special attention is paid to the history of the Russian research in the field of the Medieval Islamic philosophy. The article emphasizes the role of the most famous specialists whose works left a deep imprint on the formation of this scholarly tradition.