- Agamemnon, King of Mycenae (Mythological character)1
- Aggada2
- Agnes, Saint, Martyr1
- Agnus Dei1
- Agreda, Dominici d'1
- Agriculture6
- Agriculture--Accounting1
- Agriculture--Economic aspects1
- Ajurrūmīyah (Ibn Ājurrūm, Muḥammad ibn Muḥammad)2
- Al-Munajjim al-Kashi, Yahya ibn Imad bin Yahya1
- Alberto, Alberto di2
- Albertus de Fontanella1
- Albigenses1
- Alchemy16
- Alchemy--Bibliography1
- Alchemy--Manuscripts5
- Aldobrandini, Giovanni degli1
- Alessandri, Alessandro degli1
- Alessandri, Bartolomeo degli2
- Alessandri, Niccolò degli1