The collection consists of 53 handwritten letters from Richard Tweedy during his time in Holland with William Merritt Chase's 1903 summer abroad program, and from a later period when Tweedy lived in Paris. (One 1906 letter is from his home in New Hampshire.) The letters are mostly addressed to Tweedy's mother, Mary Alice Belcher Tweedy, while a few are addressed to his brother and to his father. Typed transcriptions of each letter are included.

Photocopy of a typescript deed documenting the sale of land in the present-day Brooklyn neighborhood of Gravesend by the American Indian inhabitants of the region to incoming English settlers. The land is referred to in the deed by its English name (Gravesend), as well as its Indian names, Narrumsum and Pootapeck. The typescript, created in 1909, is a transcription of the original manuscript deed recorded in 1665.

The provenance of this Collection Addendum is as follows: Brenda Gervertz, Executive Director of the organization from 1989-1995, donated the Records of the North American Jewish Students Appeal to the American Jewish Historical Society. Gervertz donated this additional collection, mostly detailing the latter years of the organization, in 2004.

Joseph Breck (1885–1933) served The Metropolitan Museum of Art as Assistant Curator in the Department of Decorative Arts (1909-1914), Curator of the Department of Decorative Arts (1917-1933), Assistant Director of the Museum (1917-1933) and Director of The Cloisters (1932-1933). He was closely involved with the original building plans and collection arrangement for The Cloisters. Breck was associated with numerous exhibitions, most notably the Industrial Arts Exhibitions (1918-1929). Breck was responsible for many acquisitions primarily in the field of Decorative Arts. A prolific writer, he is credited with over 200 scholarly papers, pamphlets, publications, and lectures in the fields of textiles, sculpture, furniture, as well as exhibition planning, display techniques and presentation. The Joseph Breck Records document his numerous roles within The Metropolitan Museum of Art and includes correspondence and inter-office memos with museum staff, correspondence with collectors, dealers and lenders of objects; article drafts, reports, pamphlets, catalogs and other published materials.

John Taylor Johnston was a founder of The Metropolitan Museum of Art and was elected its first President in 1870. He held this position until he retired in 1889; the institution’s Trustees subsequently voted him Honorary President for Life. The collection consists of travel journals, visitor books, correspondence, family histories, and other unpublished and published documents relating to the life, travels and family history of John Taylor Johnston. The bulk of this material relates to Johnston’s personal affairs and is not concerned with The Metropolitan Museum of Art.

A compilation of notes, correspondence, and photographs depicting philanthropist Henry Arnhold's involvement with and contributions to The New School over the course of almost eight decades. This book was created by the New School Development Office on the occasion of Arnhold's death in 2018.

Miriam Kartch (1924-) was a longtime faculty member of Mannes School of Music, starting under Clara Damrosch Mannes in 1945 and retiring in 2015. She was also director of the Preparatory Division of Mannes. This collection consists of administrative documents and personal writings from Kartch's tenure at Mannes, most dating from the 1970s to 1990s. Also includes personal notes as well as meeting minutes and other administrative records.

The Designer files collection was assembled by Kellen Design Archives staff between approximately 1994 and 2008 from a variety of sources (on occasion new files continue to be added). Subjects are typically Parsons School of Design graduates, visiting critics, lecturers, or faculty. Folder contents may include press clippings, work samples, ephemera, slides, and such printed materials as business cards, postcards, and pamphlets.

Audio and video recordings, 1999-2007, of the New York summer program of the Missouri School of Journalism, held at The New School. The program formally launched in 2000 through a partnership established by Mary Kay Blakely of the Missouri School of Journalism. The program provided students with internships, professional experience and a multimedia course of study in New York City.