lines and the entire collection cataloged and classified. Following World War II, the research and intelligence functions and staff of the wartime Office of Strategic Services were transferred to the Department of State, along with its Reference Division's library collection and extensive files of classified documents and reports. In July 1948, the library and the Reference Division were consolidated into the Division of Library and Reference Services, with John H. Ottemiller, former head of the Reference Division, as chief. Under his leadership, the Library acquired increased responsibilities and a wider perspective of service. In 1951, Ottemiller noted that "foreign affairs today encompasses consideration, planning and action reaching into all phases of human endeavor and into the remotest areas of the world. While the major subject fields of concern to the Department in foreign areas are economic, political, social, cultural and international organization affairs, the horizon of the Department is broadened today by the new concerns of such problems as military aid and science in international relations." The library's 500,000 bound volumes and one and a half million documents were available to meet the policy and operational needs of the Department. The unique value of the library's collection was revealed when a survey at this time showed that at least one-third of its titles were not duplicated in the Library of Congress. The Library collection in the years just prior to 1961 could not be accommodated in one location and was split among three buildings. The reference books were kept in a building later razed to make way for the E Street Expressway. The materials classified in the Library of Congress classification scheme A through H, were shelved in the Old Post Office Building on Pennsylvania Avenue, and the remainder, J through Z, in the State, War and Navy Building. A "jeep" messenger service ran between the three buildings, delivering and picking up books several times a day. Finally, in 1961, all the library's books and employees were moved into the new Main State Building (now named the Harry S. Truman Building). For the first time since 1945 the Library was again under one roof, and for the first time since 1875 the Library occupied its own unified quarters. Today the Library with its collection of 600,000 volumes covers more than , including four levels of stacks located between the second, third and fourth floors of the Truman Building. The introduction