The Antonow mss., 1956-1963, consists of poems by James Vincent Cunningham, Stanley Kunitz, Robert Lowell, Marianne Moore, Carl Sandburg, Sir Walter Scott, Karl Shapiro, and Richard Wilbur, all collected by lawyer Joseph P. Antonow, 1915-1990.
The Čapek mss., circa 1900-1937, consist of letters, drawings, et cetera, of or relating to Czech author Karel Čapek, 1890-1938, acquired at various times from various sources.
The Applegate mss., 1863-1929, consists mainly of correspondence between John S. Applegate, 1823-1867, and his wife Elizabeth S. (Lynch) Applegate, 1823-1890, during the Civil War, and letters from Elizabeth S. Applegate to their daughter Alma Etta (Applegate) White, 1855-1930.
The Appleton-Century mss., 1846-1962, consists of the office files of the publishing company, its two predecessors, D. Appleton & Co., and the Century Co., and to a small extent its successor, Appleton-Century Crofts, Inc.
The Archer mss., 1838-1940, consists of notes on lectures and papers written by Calvin Beza Kell Archer, 1822-1947, while he was a student at Princeton Seminary (now Hanover College) and Indiana University, 1838-1844.
The Arden, C. mss., 1938-1940, consists of twenty-eight letters from writer Edward Frederic Benson, 1867-1940, to fellow writer Lily Clive Nutt, 1888-1973, also known as Clive Arden.
The Arikha mss., 1933-2011, consists of correspondence from writer Samuel Beckett, 1906-1989, to Avigdor Arikha, 1929-2010, and Arikha's wife, poet Anne Atik, 1932-. Arikha's various collected periodicals, catalogues, theatre ephemera, criticisms of Beckett, and other related items.
The Aristotle mss., 1603-1704, consists of commentaries on the works of Aristotle. At least half of the volumes concentrate on logic, but other subjects are covered as well, including physics and general philosophy.
The Armour mss., 1952-1956, consists of letters from author Upton Sinclair, 1878-1968, to author and English professor Richard Willard Armour, 1906-1989.
The Armstrong, T. mss., 1932-1945, consists of drafts and annotated printed copies of poetic works by author Terence Ian Fytton Armstrong, 1912-1970, who published as John Gawsworth.
The Arnold mss., 1882-1899, consists primarily of letters written by British author Edwin Arnold, 1832-1904, to British India official Francis Henry Skrine, 1847-1933.
The Arthur LeRoy Kaser collection: plays by Arthur LeRoy Kaser from the twentieth century, 1927-1952, consist of 83 plays by Arthur LeRoy Kaser in 80 volumes.