This collection of 10,000+ fiche chronicles the events of the Netherlands East Indies through regular reports from the region to the Ministry of the Colonies in The Hague. Unlike the Memories van Overgave, which were a snapshot of the situation at a particular point in time, the Mailrapporten permit the study of the development of events in their continuity from the opening of the Suez Canal to the eve of the Second World War.

• Part I, 1869-1899
• Part II, 1900-1925
• Part III, 1926-1940 [1950]
• Part IV, Secret Mail Reports, 1914-1940 [1952]