The papers of rubberstamp and artistamp artist, performance artist, collector of mail art, and fine arts librarian John Held, Jr. date from 1947-2018, bulk 1973-2013, and measure 12.9 linear feet. Found within the papers are biographical material, 18 printed diaries, letters received by Held from mail artists around the world, art work consisting of artistamps designed by miscellaneous mail artists, interview transcripts, writings, project and event files, printed material, mail art sent for the Gutai Historical Survey Exhibition held at the San Francisco Art Institute in 2013, and a collection of biographical material presented by Held at a Mail Art Study Day held at the Archives of American Art in 2018.

The records of the Catherine Viviano Gallery measure 11.6 linear feet and date from 1930-1990, with the bulk of the materials dating from 1949-1978. Established in New York City in 1949, the gallery specialized in contemporary painting and sculpture primarily by American and European artists. The collection consists of artists' files; correspondence with artists, collectors, dealers, museum directors, curators, and publishers; business records; printed material; and photographs of artwork and artists. Also included are records relating to Catherine Viviano's activities as a private dealer and consultant after she closed the gallery in 1970.

The papers of New York museum director and independent curator Thomas M. Messer measure 4.6 linear feet and date from 1949-2010. Material includes correspondence, a diary transcript, and printed material that reflect Messer's long career, primarily as director of the Solomon R. Guggenheim Foundation. Correspondence comprises the bulk of the collection and documents the relationships he built with artists, art historians, curators, and others colleagues. Notable correspondents include Francis Bacon, Will Barnet, Larry Bell, Alberto Burri, Pol Bury, Marc Chagall, Chryssa, Jean Dubuffet, Max Ernst, Dan Flavin, Helen Frankenthaler, Alberto Giacometti, Richard Hamilton, Jean Hélion, Grace Knowlton, Rosemarie Koczy, Jirí Kolár, Katharine Kuh, Agnes Martin, Henry Moore, George Rickey, Charles Simonds, Clyfford Still, Jack Tworkov, and many others.

The papers of art historian, dealer, critic, and curator Katharine Kuh measure 12 linear feet and date from 1875-1994, with the bulk of the material dating from 1930-1994. The collection documents Kuh's career as a pioneer modernist art historian and as the first woman curator of European Art and Sculpture at the Art Institute of Chicago. Found within the papers are biographical material; correspondence with family, friends and colleagues; personal business records; artwork by various artists; a travel journal; writings by Kuh and others; scrapbooks; printed material; photographs of Kuh and others; and audio recordings of Kuh's lectures and of Daniel Catton Rich reading poetry.

Walter Friedrich Knips was a commercial attaché for the German foreign service. He served in Karachi, Pakistan, from 1952 to 1957. The film footage included in this collection covers trips taken by Knips and his family to Hunza, Srinagar, Gilgit, and Nanga Parabat between 1953 and 1955 and family home movies from Pakistan and Houston dating from 1952 to 1960.

The papers of painter Harriet Blackstone date from 1870-1984 and measure 5.4 linear feet. The collection provides documentation of Harriet Blackstone's career through scattered biographical material; personal and professional correspondence, including letters from Maria Oakey Dewing, Thomas Wilmer Dewing, Alice Tisdale Hobart, Joseph Cummings Chas...

The Rose Fried Gallery records measure 8.1 linear feet and date from 1936 to 1972 with the bulk of materials dating from 1945 to 1970. The majority of the collection consists of artists files documenting the gallery's relationship with abstract, modern, and Latin American artists; additional named subject files; and scattered administrative and financial files. Individual artists and subject files contain a wide variety of documentation, such as correspondence, photographs, financial records, and printed materials.

The papers of painter and naturalist, Abbott Handerson Thayer, and the Thayer family date from 1851 to 1999, with the bulk of the material dating from 1881 to 1950, and measure 5.12 linear feet. Thayer's painting career, interest in concealing coloration (camouflage) in nature, and relationships with artists, patrons, family, and friends are documented through correspondence, writings, scattered legal and financial records, printed materials, and a scrapbook. Photographs are of Thayer, his family, studio, and friends, including artists. The collection also contains family papers created by his second wife, Emma Beach Thayer, his son Gerald, his daughters Mary and Gladys, and Gladys' husband David Reasoner, who managed Thayer's estate after his death.

The Staempfli Gallery records measure 5.2 linear feet and date from 1958 to 1992. Scattered administrative and financial records, correspondence, sales invoices, inventory records, and exhibition catalogs document the business activities of this New York gallery.

The records of Milch Gallery measure 42.5 linear feet and date from 1911-1995. Edward Milch (1865-1953) opened the Edward Milch Gallery in New York City. In 1916, he formed a partnership with his brother Albert Milch (1881-1951), a gilder and framer, creating E. & A. Milch, Inc., a gallery specializing in American art. Harold C. Milch (1904-1981), Albert's son, was appointed a partner in 1944 and continued the business until his death. Business records of Milch Gallery, 1911-1968, include correspondence, sales records, inventories, financial records, printed matter, photographs, and legal documents. Later additions to the records date from 1922-1995 and include correspondence; artists' files; financial, sales, and stock records; printed material; and photographs.