Collecting on the Americas began after the end of World War I and at first included items from the governments of Argentina, Bolivia, Chile, Costa Rica, Panama, and Peru, who were represented at the Paris Peace Conference in 1919. Additional materials were later received from nine other Latin American states and from four British colonies in the Caribbean.
In the following years, library representatives continued to collect materials in the United States and also made expeditions to Latin America in order to establish a network of resident agents there, especially in countries where the book trade was poorly organized. As a result a number of important collections came to Hoover, including the Inquiry Papers, an extensive set of documents of a group of American scholars and experts, and the Documents of the Special Neutrality Commission of the Pan-American Union. By the mid-1930s the library possessed a significant Latin American collection.
The acquisition of materials related to the United States was active during World War I, resulting in the acquisition of letters, memoranda, and documents relating to the activities of governmental boards and agencies; books and pamphlets dealing with U.S. military participation in the war; manuscript reports, records, and personal narratives by American combatants; and official histories.
From the beginning of World War II, the Institution collected materials on that conflict. This included the papers of military leaders and documents on methods of U.S. psychological warfare, as illustrated by many collections of propaganda leaflets acquired from both the Pacific and the European theaters. Various aspects of civilian opposition to and participation in the war were documented through the acquisition of publications and records of political groups, committees, peace societies, relief organizations, churches, women's organizations, and business firms.
After World War II, the Institution emphasized the themes of communism, anticommunism, and socialism in the United States; U.S. foreign relations; and military policy. Concerted attention was given to the Korean and Vietnam Wars, for which holdings include position papers, policy statements, newspapers, and journals reflecting national and international movements and associations. Papers of individuals and private organizations have been collected, as well, particularly as they relate to ongoing efforts to establish peace.
As the United States became involved in World War II, interest and activity in Latin American studies decreased, resulting in a dramatic reduction of the Institution's collecting in that area. In 1954 it was agreed that Stanford University Libraries would be responsible for Latin American materials. Hoover accordingly transferred most of its holdings on Latin America to the university library, with Hoover continuing to collect archival materials on Latin America. This arrangement was in effect until 1962, shortly after Fidel Castro took power in Cuba, when the Hoover Institution resumed its collecting activities on Latin America.
Thus, Joseph Bingaman was made curator of the collection in 1963 and continued in that position until 1986. In 1986 William Ratliff became curator, and he continues in that capacity today. In 1994, collecting responsibility for Latin American library materials was again transferred to Stanford University Libraries, though Hoover continues actively acquiring archival materials from the area. The interests of the past continue today, but since the beginning of the 1990s, attention has been focused on the emergence of democratic governments and market economies in the region and the impact of globalization.