- Asceticism--Early church1
- Ashburnham, Bertram Ashburnham, Earl of, 1797-18781
- Assassination1
- Assumption of the Blessed Virgin Mary3
- Astrolabes9
- Astrology10
- Astrology, Arab9
- Astrology, Iranian1
- Astronomical instruments3
- Astronomy27
- Astronomy, Ancient1
- Astronomy, Arab21
- Astronomy, Arab--Tables4
- Astronomy, Greek2
- Astronomy, Medieval4
- Astronomy--Tables1
- Athīr al-Dīn al-Abharī, al-Mufaḍḍal ibn ʻUmar, -1265. Hidāyat al-ḥikmah2
- Atlases1
- Atlases (Geographic)20
- Aubigné, Agrippa d', 1552-16301