The collecting of books and archival materials started even before the founding of the Minority Institute in 1925; later on the book collections of the Department for Border Issues of the Scientific Institute, collected during and immediately after World War II, were added. After 1948, the Institute acquired not only current materials but also some other older archival funds from the inter-war period. The library stores about 38.000 books and periodicals, plus newspaper clippings, journals and monographs.
Today the rich and nationally very significant funds (500 files) comprise the Archives of the Office for the Occupied Territory (1918–1921), Archives of the Interallied Plebiscite Commission, the SHS (State of the Serbs, Croats and Slovenes) section in Ljubljana (1918–1920), Archives of the Commission for Peace Conference with the National Government of the SHS in Ljubljana (1918–20), Archives of the National Council for Carinthia in Volkermarkt-Velikovec (1919–1920), the Carinthian Plebiscite (1920) and the Paris Peace Treaty (1947), as well as personal archives of important cultural and political representatives of Slovenes in the neighbouring countries. Special mention should be made of the Archives of Josip Vilfan (over 40 files), which had previously been kept at the Historical Archives Ljubljana and are presently again available at the IES. Recent addition to the library was a donation of books on the crisis in the former Yugoslavia.