Collecting from the area between Germany and Russia began immediately after World War I. Professor E. D. Adams, from the Stanford University History Department, on Herbert Hoover's initiative, went to Paris with a team of specialists to gather documentation on the war and the subsequent Peace Conference. All conference delegations from East/Central Europe were contacted, including those representing existing states and those with claims for statehood. Most delegates were cooperative, providing large amounts of material that formed the basis of the Hoover War Library, as it was then called. Particularly detailed documentation was obtained from Poland, Czechoslovakia, Romania, and Yugoslavia, initiating what was to become a great tradition of Hoover on-site collecting of library and archival materials in this part of the world.
Furthermore, a member of the Adams team, Professor Ralph H. Lutz, visited Warsaw in September 1919 at the invitation of the Polish delegation, initiating what was to become a great tradition of Hoover on-site collecting of library and archival materials in East/Central Europe. Building on this solid foundation in the years that followed, contacts were established and strengthened throughout East and Central Europe, often by persons connected with the American Relief Administration, which Herbert Hoover directed.
As with Western Europe, collecting in East/Central Europe was interrupted by events surrounding World War II. Earlier collecting investments and contacts paid off after the war, however, as a massive amount of wartime materials was delivered to the Hoover Institution. Many of these materials were unique clandestine publications and items issued by the German occupiers. In other cases, political and military authorities, in an effort to protect the archives from dispersion, transferred collections under their control to a safe location in the United States: the Hoover Institution.
More recent collecting efforts have concentrated on current political ephemera, such as posters, leaflets, newspapers, and pamphlets (often published secretly), published books, and periodicals; and the archival documentation of the communist regime and its adversaries, the democratic opposition. Of particular note was the Hoover Institution's decision to have its curator for Eastern Europe, Maciej Siekierski, reside in Warsaw during 1991-1993. This greatly enhanced collecting in the area as he oversaw the acquisition and shipment of several tons of materials on Poland and Eastern Europe.