The Harold Nicolson Papers consists of papers of the English diplomat, journalist, and biographer Harold Nicolson (1886-1968). These papers primarily contain correspondence received by Nicolson, but there is also a large series of letters written by Nicolson to Richard Rumbold, as well as a few to others. Also included in the collection are manuscripts and/or working notes for four of Nicolson's published works. Furthermore, there is a small amount of papers of others, chiefly correspondence by and to Nicolson's wife, "Vita" (Victoria) Sackville-West.

Consists of a closed collection of more than 5,000 Western Americana photographs, consisting mostly of documentary photographs of the Trans-Mississippi West from the late 1860s to early 1900s, largely from the perspective of white photographers and settlers. Subjects include American Indians (especially studio portraits), natural wonders, cities, towns, buildings, and economic activities (mining, railroads, logging, and agriculture). Some photographs relate to the Indigenous populations of Mexico and Central America. The dimensions, physical formats, and photographic processes of the photographs vary widely.

Consists of the papers of Hungarian-born, Nobel Prize-winning physicist Eugene Wigner, and includes correspondence, subject files, writings, and offprints reflecting his long career in physics.

Bruce and Beatrice Blackmar Gould were co-editors at the Ladies' Home Journal in the mid 20th century. Bruce Gould also worked with the Saturday Evening Post. Their correspondence includes letters between Bruce and Beatrice about their co-editorship and co-authorship, letters with writers for the Ladies' Home Journal, and letters from actresses about the Ladies' Home Journal. Also included is a collection of letters about Marion Crawford's book The Little Princesses, some of Beatrice's speeches, speeches by others, and printed matter.

The Princeton Nassoons are a close-harmony, all male, student a cappella group that formed in the late 1930s. The collection consists primarily of the Princeton Nassoons' original musical arrangements and correspondence.

Charles W. Yost (1907-1981) led a varied career as a diplomat, United Nations representative, writer, and scholar. He was a member of the foreign service intermittently between 1930 and 1971, after which time he devoted himself full-time to writing and teaching. Yost's papers document his professional life in the Foreign Service, as well as his time in academia, and include his correspondence, writings, and photographs.

The organization that became Americans United for Separation of Church and State was founded in 1947 to protect church-state separation and religious freedom, as well as to educate lawmakers, religious leaders, and the general public regarding Constitutional religious liberties. The records document the administration and issues of the organization from its founding and include correspondence, meeting materials, and publications.

The Selected Papers of Harper & Brothers consist primarily of the editorial and business correspondence of Harper & Brothers, a distinguished publishing firm, between 1909 and 1960.

Jeffrey Fuller (1917-1970) worked for the American Civil Liberties Union (ACLU) from 1948 to 1966 and also served in the U.S. Army during World War II. Fuller's papers document his service in the U.S. military and his work for the ACLU and include his personal and professional correspondence, memoranda, and diaries.

Consists of files created by P.E.N. American Center as part of its regular business operations since its founding in 1922. Includes material on governance and policies, programs, awards, and financial aid granted to authors, and the center's involvement with International P.E.N. and other P.E.N. organizations worldwide. The collection is especially notable for its extensive author correspondence and occasional original manuscripts, as well as audio and video recordings of P.E.N. programs and events.