Series 1: Biographical Material/Reading Lists consists of three folders, the first containing biographical sketches, most geared toward submission to the editor of Who's Who in America. The second folder contains articles concerning Earle's education and career (e.g. Earle's Armistice Day Speech in November 1941). Earle's personal reading lists include lists of American History volumes and assorted fiction titles.

Series 2: American Committee for International Studies [ACIS], (1932-1948) consists of the records of ACIS, formerly known as the American Coordinating Committee for International Studies. ACIS represents an expanded version of the original committee. The American Coordinating Committee was established in 1936 to take the place of the Council on Foreign Relations as the American member of the International Studies Conference, a conference organized in 1928 that cultivated a program of studies in countries with member groups. The Council on Foreign Relations became the administrative agent for the American Coordinating Committee. The Committee was composed of representatives of the Council on Foreign Relations, the Foreign Policy Association, the Institute of Pacific Relations, the National Committee of the United States on International Intellectual Cooperation, and university members appointed by the Social Science Research Council.

Series 3: Correspondence, (1936-1954), is arranged alphabetically with the items within each folder arranged in reverse chronological order. It consists of correspondence exchanged between Earle and various individuals in the military, the federal government, academia, business, and University publishing. There are general alphabetical files, as well as separate folders for individuals with whom Earle had substantial correspondence. Prominent correspondents include: Herring Pendleton (President, Social Science Research Council and Assoc. Executive, Carnegie Corp. -- 1947-1948), Jacob Viner (Department of Economics, University of Chicago, -- 1944-1945), Sir John Slessor (Chief Air Marshall, R.A.F.-- -1948-1951), and William S. Culbertson (Chief, Geopolitical Section, MIS [Military Intelligence] -- 1942-1943).

Series 4: Professional Activities, (1937-1954) is arranged alphabetically within six subseries: The Princeton Military Studies Group, Government Consultant/Advisor, Professional Associations (other than ACIS), Professional-Related Activities, Conferences, and Interviews. The series consists primarily of correspondence, with some government reports, committee minutes, and news clippings interfiled. The Princeton Military Studies Group subseries reflects the activities of a group of scholars established by Earle to study broad questions of national strategy, military security, elements of military and economic power, and the role of the United States in world politics. The Government Consultant/Advisor subseries illustrates Earle's extensive work with federal government offices during World War II (especially with the Army Air Forces, Headquarters). Within the Professional Associations subseries, there is a substantial amount of material on Earle's involvement in the Council on Foreign Relations [CFR]. Aside from a number of general CFR folders, there are folders containing reports and correspondence of various CFR study groups, most substantially the Study Group on Anglo-American Relations (1952). The drafts of this study group's report are listed in the box listing. This subseries also contains a substantial amount of material on Earle's role as a trustee of the Foundation for the Advancement of the Social Sciences (based at the University of Denver). The Professional-Related Activities subseries highlights Earle's part in instigating citizen involvement in the War Effort and in several government projects. Information regarding a number of military policy conferences with which Earle was involved are contained in the Conferences subseries. The Interviews subseries contains dictations of interviews conducted by Earle with individuals such as Charles Dollard and Frederick Keppel of the Carnegie Corporation and Joseph H. Willets of the Rockefeller Foundation.

Series 5: Research Files (World War I-World War II and Post-World War II), consist of outlines of Earle's lectures and article drafts on a variety of topics and accompanying research notes, news clippings, reports, excerpts from books, and bibliographic citations. The series is divided into two parts -- World War I - World War II files and Post-World War II files. Both subseries are arranged alphabetically by research subject. Topics included in the World War I-World War II files are Air Power (various theories on), National Security, and Post-War Settlements. Also included are several folders on American History, particularly relating to Revolutionary America. Although not specifically about World War I and World War II, these files may have been used to shed perspective on relevant issues. The Post-World War II files include such topics as American foreign policy, Anglo-American and Franco-American relations, and civil-military relations. Clippings and articles from The Economist, The New York Times, The Herald Tribune, and Atlantic Monthly represent the majority of the accompanying material. The decision was made not to keep files containing solely clippings and other materials collected by Earle as part of his "general research" (i.e. not accompanying lecture outlines or other drafts). This decision was based on the assumption that the sources Earle consulted for his published writings would be noted as citations in the bibliographies of those works.

Series 6: Writings is composed of several types of materials. The first subseries, Related Correspondence and Other Materials, consists of correspondence regarding Earle's writings (lectures, letters to the editor, book reviews, books, and articles), as well as related materials such as clippings and reviews and some drafts. The second subseries, Drafts and Typescripts, contains drafts of some of Earle's lectures, syllabi, and various memoranda and notes (authored by Earle as well as by The Princeton Military Studies Group). The third subseries, Publications, contains published articles, books and book reviews. Within the Articles/Reports sub-subseries of Publications, the published articles are arranged according to the journal in which the article was published. Within the Books sub-subseries of Publications, the materials are arranged according to Earle's role in the publication process--author, editor/co-author, or author of an introduction or forward. The books most worthy of note include Nationalism and Internationalism (essays inscribed to Carlton J.H. Hayes) and Modern France. Also of note is Halford J. Mackinder's Democratic Ideals and Reality, for which Earle wrote the introduction.