- Agassiz, Louis, 1807-18731
- Agricola, Georg Andreas, 1672-17381
- Agrippa von Nettesheim, Heinrich Cornelius, 1486?-15351
- Agron, Edouard1
- Airplanes2
- Airy, George Biddell, 1801-18921
- Akenside, Mark, 1721-17702
- Albany Medical College. Library2
- Albinus, Bernhard Siegfried, 1697-17704
- Alchemy248
- Alcock, Rutherford, Sir, 1809-18701
- Aldrovandi, Ulisse, 1522-1605?2
- Alexander, John, 1891-19541
- Allen, Charles J.1
- Allen, Edgar van Nuys, 1900–19611
- Allen, H. Homer1
- Allen, Nancy B.1
- Allen, Willard M., 1904-19931
- Alpha Kappa Kappa3
- Althaus, Julius, 1833-19001