- Astrology, Arab1
- Astronomical instruments1
- Astronomy, Ancient1
- Astronomy--Popular works1
- Audiore, Antonio1
- Aurispa, Giovanni, approximately 1376-14591
- Austria--Lambach (Upper Austria)1
- Authors, Latin1
- Autograph albums1
- Aveiro, Gabriel de Lencastre, Duque de, 1667-17451
- Baptism1
- Baptism of Jesus Christ1
- Barbara, Saint1
- Barbarossa, -15461
- Bardi, Giovanni de', conte di Vernio, 1534-16121
- Barrois, Joseph, approximately 1785-18551
- Bartholomeo, de Soncino1
- Bartholomew, of San Concordio, 1262-13471
- Bartoli, Dianora1
- Bartoli, Giannozzo1