The Asquith mss. II, 1881-1957, consists primarily of the letters of English writer and journalist Charles Whibley, 1859-1930, to English novelist Lady Cynthia Asquitch, 1887-1960.
The Astle mss., 1795-1797, consists of the letters and memoranda of Andrew Stuart, 1725-1801, Scottish lawyer, to Thomas Astle, 1735-1801, English antiquary and paleographer.
The Auchincloss mss., 1928-1935, consists of materials that were removed from Lilly Library copies of books by poet Edwin Arlington Robinson, 1869-1935. The books formerly belonged to broker Charles C. Auchincloss, 1881-1961.
The Augustan mss., 1688-1748, consists of manuscripts and correspondence collected by Indiana University Professor William T. Morgan, 1922-1945, relating to the Age of Queen Anne.
The Avallone mss., 1962-1984, consists of letters from author Robert Albert Bloch, 1917-1994, in Los Angeles, California, to writer Michael Avallone, 1924-1999, in New Jersey.
The Ayelsford mss., 1941-1968, consists primarily of correspondence, articles, photographs, and miscellaneous material collected by friar Father Brocard Sewell, 1912-2000, during the years he edited The Aylesford Review, a literary quarterly sponsored by the British Carmelites, 1955-1968.
The Baker, Hord, and Hendricks mss., 1862-1916, consists of records of the Indianapolis, Indiana, law firm founded in 1862 by Thomas Andrews Hendricks, 1819-1885, and Oscar B. Hord, 1829-1888.
The Baker, K. mss., 1958-1978, consists of correspondence, manuscripts, and other materials of modern authors collected by businessman Keith Baker, 1906-1986.
The Baker Street Irregulars mss., 1923-2007, consists of correspondence, business files, and publications of the Baker Street Irregulars, a Sherlock Holmes literary society founded in 1934.