The Printed Matter series consists of clippings and magazines that contain articles about the Middle East, particularly Saudi Arabia. Many of the articles refer to Twitchell and his work in the region.

The Maps, Plans, Drawings series contains printed maps published by official agencies or corporate bodies and includes the United States Geological Survey Saudi Arabian map series in various years, nautical charts, and other planimetric maps. The most notable maps include project-specific hand drawn maps, printed maps in Arabic, and mine survey maps. Also included are equipment drawings. Other maps may also be located within project or country files in Series 3: Topical Files.

Series 7: Oversize Materials contains scrapbooks and large-scale geographical and nautical maps.

Series 6, Photos and Memorabilia, circa 1941-1984 contains a small number of photos, with the bulk from the 1970s. This also includes the photos used in Tangled Web. It also contains a large framed copy of the covers of the first and last edition of Foreign Affairs that Bundy edited.

The Correspondence series contains some of Clark's father's correspondence, particularly a letter signed by J. Edgar Hoover. Included in Clark's own correspondence are thank you notes and informal letters from John F. Kennedy and Jacqueline Kennedy Onassis. The notes are conversational in tone. Letters signed "Jack" are from his days in the House of Representatives and the Senate. Kennedy also thanks him for gifts and congratulates him on a new job. Mrs. Kennedy thanks Clark for Christmas gifts, discusses a wedding present to Clark's son, and looks forward to visiting with him on Martha's Vineyard.

The Correspondence Series includes letters, notes, and telegrams from a variety of individuals, usually to or from Woodrow Wilson (although some correspondence is between others and is related to Wilson). Perhaps the most notable portion of this series is the Wilson family correspondence, including letters between Wilson and his first wife, Ellen Axson Wilson, from their courtship through the end of her life in 1914, as well as correspondence to and from his daughters Jessie and Margaret, and his brother-in-law Stockton Axson. This series also includes a "Special Correspondence Collections" section, which contains shorthand notebooks of Wilson letters recorded by his secretary, Gilbert Close, as well as correspondence collections of other individuls close to Wilson, including Lawrence Woods, David Huston, and Mary Hulbert, as well as the Thackwell collection of correspondence between Woodrow family members and especially between Woodrow Wilson and his cousin, Harriet Woodrow. These collections include letters to and from Wilson and others. The final section of the Correspondence Series includes copies of letters in other collections.

The Documents Series includes originals and photostats of many important documents written, signed, or received by Woodrow Wilson, including applications, appointments, constitutions, resolutions, and property and deed documents. Of note are the marriage license of Woodrow Wilson and Edith Bolling Galt, as well as "Resolutions Regarding the Graduate School of Princeton University, 1908."

The Images, Portraits, Photographs, Caricatures Series contains etchings, prints, photographs, lithographs, and paintings of Woodrow Wilson, his family and associates, his residences, and related topics visually documenting his life. The series includes the G. E. Thompson Collection, as well as many miscellaneous and oversized images.

The Printed Matter Series consists of printed matter by and about Woodrow Wilson, mainly printed addresses, speeches, and cartoons in newspaper and printed forms.

The Papers of Others About Woodrow Wilson Series consists of groups of papers collected by others about Woodrow Wilson. The collectors include writings, correspondence, documents, and photos collection by family (Stockton Axson, Eleanor Wilson McAdoo, and Margaret Wilson), along with writings such as reminiscences, theses, or dissertations on Wilson and correspondence collections on Wilson (Wilson Farrand, McMillan Lewis, William McCombs). Also included in this series is the Henry Bragdon Collection of Reminiscences (made up of interviews and correspondence on Wilson), papers of Laura Turnbull, the Curator of the Woodrow Wilson Collection, on her work for Woodrow Wilson: A Selected Bibliography of his Writings, Addresses, and Public Papers, and some files of the Woodrow Wilson Foundation. Finally, the series includes the papers of Charles L. Swem, Wilson's stenographic secretary, including shorthand notebooks, transcriptions of speeches, correspondence, and interviews recorded from 1912-1921, as well as photographs, and documents, divided into sections on Wilson and on personal topics, and a collection of newspaper clipping scrapbooks on Wilson from the Woodrow Wilson Foundation and individuals.

The Biographical Materials series contains newspaper articles about Derso and Kelen and other biographical ephemera like business cards, press passes, and advertisements for their syndicated cartoons and writings. Exhibition catalogs are included in this series. Of particular note is an essay written by Betty Kelen, Kelen's wife, providing a brief, but personal and humorous view of Derso and Kelen's friendship and artistic careers.

The Correspondence series consists primarily of personal letters each artist received from friends and colleagues and sometimes from publishers. Notably, the majority of the letters are written in Hungarian with a few letters in French, English and German.

The Writings series documents Derso and Kelen's secondary careers in writing, which began after World War II. Derso's writings consisted of a few essays published in the New York Times and a proposal for an 'art book' of portraits of Jewish statesmen, diplomats, and writers submitted to the Conference on Jewish Material Claims Against Germany for which he received a fellowship. There is also a skeletal draft script for a motion picture on the history of the League of Nations.

The Art Works series forms the bulk of this collection and consists of over 900 cartoons and caricatures created in simple media like pencil sketches or ink drawings to formal limited edition portfolios of lithographs or richly hued watercolors. The vast majority of the works were produced between 1920 and 1950, the active period of collaboration between Derso and Kelen. Once their artistic partnership ended in 1950, Kelen produced cartoons and drawings for United Nations' publications and his own personal book projects and Derso supplied the National Review with numerous portrait sketches for their articles.

This Menu Cards series consists of menu cards created by Derso and Kelen for press luncheons in honor of the journalists accredited to the League of Nations from 1925 to 1937 and menu cards for social occasions or dinners honoring high level officials at the United Nations in the late 1940s and early 1950s. One menu card created for the first League luncheon in October 1925 that marked the conclusion of negotiations for the Treaty of Locarno is signed by each of the diplomats represented on the card. There are also 'cards in progress' with annotations and cut-and-paste elements by the artists.

The Miscellaneous series includes material not related to the other series in the Derso and Kelen Collection and contains photographs depicting the artists as well as some photoreproductions of their works. Of interest is a photograph of Derso and Kelen sitting with Mrs. Franklin D. Roosevelt as she admires the drawing of herself by Derso and Kelen that appeared in the United Nations Sketchbook. There is also a tattered copy of Modern Caricaturists by H. R. Westwood published in 1932 by L. Dickson, Ltd. that includes a chapter on Derso and Kelen. Another item in this series is a guest book from an exhibition in 1976.

The Oversize Cartoons series consists of oversize cartoons and illustrations listed by title. When known, the publishing history of the work is noted along with the date of the work and whether the work is monochromatic or color.

The material added to the original donation represents an expansion of the established series. Of note is the greatly expanded series of published and unpublished writings almost exclusively by Kelen and ranging in date from 1950 to 1975. The writings include proposals and manuscripts for unpublished illustrated books, newspapers columns, and short essays and manuscripts for published works including Peace in Their Time and the newspaper column, On Second Thought.