The Correspondence series contains Widenmann's professional correspondence with bankers, businessmen, government officials, and academics. The majority of the letters are in response to Widenmann's requests for copies of articles or speeches, often with the requested item and sometimes with Widenmann's comments on the item. The series also includes correspondence between Widenmann and United States government officials regarding his views of financial policies, Widenmann writing colleagues about the state of the stock market and United States financial conditions more generally, correspondence in relation to his involvement with professional organizations and conferences, and invitations to events.

The Topical Files series contains copies of articles, speeches, testimonies before Congress, press releases, memoranda, and publications collected by Widenmann on a variety of subjects. The subjects include monetary, financial, and economic conditions in the United States and internationally, United States government financial and economic policies, gold, the stock market, business, and reports on the performance of individual businesses. The materials were produced by banks and businesses, professional organizations, scholars, and businessmen.

The Writings series includes Widenmann's writings for use within Loeb, Rhoades Company and drafts of articles and speeches presented to the financial, economic, and business communities. The subjects of his writings include monetary problems, gold and the gold standard, the United States economy, and the money and stock markets. The reports for Loeb, Rhoades Company include analysis of these same subjects, as well as discussions about the performance and strategies of the company. The series also includes a few reports written while Widenmann was an executive at Ludwig Bendix's firm, and a few of Widenmann's student papers.

The Research Files series contains notes, drafts, and correspondence related to Ryder's various projects. Additionally, some folders contain finished publications.

The Teaching and Administrative Files series contains correspondence, notes, drafts, publications, and teaching materials related to Ryder's academic posts. There is a small amount of personal correspondence.

The Publications series consists largely of the published results of Ryder's research. There are a small number of notes, drafts, and correspondence scattered throughout.

These records are composed of mostly correspondence and subject files that were created in the course of Ullman's work as an academic, primarily at Princeton University, and in various other positions he held during his career, such as his term on the editorial board of The New York Times. The records also include some of Ullman's published articles and what appear to be notes and research prepared for lectures on European governments and foreign policies. Of note is Ullman's correspondence with well-known individuals in the field of foreign policy, particularly George Kennan.

This portion of the collection includes correspondence, reviews, and research materials that pertain to Ullman's first published scholarly work, the three-volume Anglo-Soviet Relations, 1917-1971.

Series IV: Personal Materials includes a letter written by H. Freeman Matthews, Jr. to his parents while in the army in 1947 as well as candid photographs and photographs of friends and colleagues.

Personal correspondence to family and friends. These materials are not in any particular order; many letters remain in original envelopes.

Series 4, General, 1944-2012 reflects Becker's personal activities. Becker used his financial and analytical skills throughout his career. He created a small file of his position papers, included are documents for the Investment Bankers Association of America, John J. Gilhooley during his bid for New York City Comptroller in 1961, and the Critical Issues Council directed by Milton Eisenhower. Some of these position papers can be found elsewhere in the series, for example the paper on the position of comptroller is found in the portfolio assembled by Becker and within the John Gilhooley correspondence. Other writings in this series include the foreign press reviews from Becker's Army service in the mid-1950s, and a manuscript entitled "Selling Municipal Bonds."

Series 1: Diary, Correspondence and other writings by Philip Strong includes diaries from 1919 and 1921, some poems and short stories probably written by Philip Strong, 1966 articles and notes, and correspondence of a personal and professional nature from 1947 to 1963.

Series 2: Bibliographies, Indexes and Abstracts contains selected bibliographies of materials related to espionage and counter-intelligence. Also included are indexes to the National Defense Review of 1955 and a list of hearings, reports and cases related to Communist propaganda in the United States.

Series 4: Articles, Essays etc. by Authors other than Philip Strong includes articles, essays, and reports relevant to Strong's interests in espionage and counterintelligence.