Uşakizâde Muammer Bey (1875-1951), who was Atatürk's father-in-law and the uncle of Halid Ziya (Uşaklıgil), owned the Gulf Ferry Business from 1923 to 1925. This collection includes correspondence of the director of Gulf Ferry Business with various individuals and institutions, as well as notebooks that contain copies of his correspondence with Muammer Bey.