- Manuscripts, Italian1
- Manuscripts, Latin17
- Manuscripts, Latin (Medieval and modern)66
- Manuscripts, Medieval130
- Manuscripts, Renaissance51
- Manuscripts, Spanish1
- Manuscripts, Yiddish2
- Marginalia7
- Marriage1
- Marriage (Canon law)1
- Marriage--Moral and ethical aspects1
- Martinus, Polonus, -12791
- Martyrologies1
- Mary, Blessed Virgin, Saint3
- Mary, Blessed Virgin, Saint, in the liturgy1
- Mass--Celebration1
- Massachusetts--Boston30
- Massachusetts--Northampton1
- Massachusetts--Williamstown1
- Mathematics1