- Agnes de Lima collection of Alyse Gregory (YCAL MSS 164)2
- Aileen Pringle papers (YCAL MSS 56)2
- Alain Arias-Misson papers (GEN MSS 1514)4
- Alan Hovhaness letters to Judith Malina (YCAL MSS 359)10
- Alan Pryce-Jones papers (GEN MSS 513)25
- Album of watercolors and drawings. (GEN MSS 831)11
- Aleksander Wat papers (GEN MSS 705)39
- Aleksis Rannit papers (GEN MSS 715)3
- Alexander Metcalf Fisher Papers (GEN MSS 1473)9
- Alexander Pope collection (GEN MSS 270)1
- Alfred Austin collection (GEN MSS 219)1
- Alfred Corn papers (YCAL MSS 605)4
- Alfred E. Heller collection of world's fair material (GEN MSS 734)20
- Alfred Schutz papers (GEN MSS 129)23
- Alfred Stieglitz / Georgia O'Keeffe archive (YCAL MSS 85)580
- Alfred Stieglitz / Georgia O'Keeffe collection (YCAL MSS 104)12
- Alfred White Van Sinderen collection of Charles Babbage (GEN MSS 1362)1
- Alfredo de Palchi and Sona Raiziss papers (GEN MSS 947)1
- Algernon Swinburne collection (GEN MSS 303)3
- Alice Raphael Papers (YCGL MSS 21)1