- Association of the Bar of the City of New York1
- Astor, John Jacob, 1763-18481
- Astor, John Jacob, 1791-18691
- Astor, John Jacob, 1822-18901
- Astor, William B. 1792-18751
- Ateshoglou, A. D1
- Atkins, Thomas Astley, 1839-19161
- Atkins, Zoë1
- Atlantic Publishing and Engraving Company (New York, N.Y.)1
- Atlass, Beatrice1
- Atwater, W. O. 1844-19071
- Atwell, Benjamin H1
- Automobile Club of America1
- Automobile Club of New York1
- Avenue of the Americas Association, Inc1
- Avery Classics (Offsite) copy: From the library of Seymour Durst with his bookplate2
- B. Altman & Co3
- B.F. Goodrich Company1
- B.M. Cowperthwait & Co1
- Bache, A. D. 1806-18674
- Bachmann, John, active 1849-18852
- Bacon, Edgar Mayhew, 1855-19352
- Bacon, Edmund N1
- Bader, Louis, 1921-1
- Bailey, R. T1
- Bailey, Vernon Howe, 1874-19531
- Bainbridge, Lucy Seaman, 1842-19281
- Baird, Charles W. 1828-18871
- Baker, Donald M1
- Baker, Geoffrey H1
- Baker, John F1
- Baker, John, active 18131
- Baker, Voorhis & Co1
- Baker, William Spohn, 1824-18971
- Baldwin, Ebenezer, 1790-18371
- Baldwin, Henry, 1780-18441
- Bales, Carter F1
- Ballinger, J. Kenneth 1900-1
- Baltimore and Ohio Railroad Company1
- Bancroft, Aaron, 1755-18391
- Bancroft, Frederic, 1860-19451
- Bank Convention1
- Bank for Savings in the City of New York1
- Bank of New York1
- Bank of New York and Trust Company2
- Bank of the Manhattan Company2
- Banks, David, active 18911
- Bannerman, Francis1
- Baragwanath, Albert K., 1917-20061
- Barber, John Warner, 1798-18851
- Barbour, James, 1775-18421
- Barbour, Thomas, 1832-18851
- Bard, Samuel, 1742-18211
- Bard, William, 1778-18531
- Barker, A. J1
- Barker, Jacob, 1779-18711
- Barker, Wendell Phillips, 1884-1
- Barnes, Edward Larrabee, 1915-20041
- Barnett, Jonathan1
- Barnum's American Museum1