- Astronomy, Greek2
- Astronomy, Medieval10
- Astronomy--Tables3
- Athīr al-Dīn al-Abharī, al-Mufaḍḍal ibn ʻUmar, -1265. Hidāyat al-ḥikmah2
- Attila, -4531
- Augsburg Confession1
- Augustine, of Hippo, Saint, 354-4304
- Augustinians2
- Aurispa, Giovanni, approximately 1376-14591
- Austria--Lambach (Upper Austria)1
- Austria--Vienna1
- Averroës, 1126-11981
- Azharī, Khālid ibn ʻAbd Allāh, -1499. Sharḥ al-Ājurrūmīyah1
- Bahai Faith2
- Bahai Faith--Sacred books1
- Bakers1
- Balances (Weighing instruments)1
- Banks and banking2
- Baptism1
- Baptism of Jesus Christ1