- Manuscripts, Greek1
- Manuscripts, Greek (Medieval and modern)1
- Manuscripts, Hebrew1
- Manuscripts, Italian19
- Manuscripts, Latin138
- Manuscripts, Latin (Medieval and modern)38
- Manuscripts, Medieval96
- Manuscripts, Persian1
- Manuscripts, Renaissance158
- Manuscripts, Spanish1
- Manuscripts, Turkish1
- Maps1
- Marginalia3
- Massachusetts--Boston6
- Massachusetts--Wellesley2
- Massachusetts--Williamstown4
- Materia medica, Vegetable1
- Matthei, Bernardino1
- Medea, consort of Aegeus, King of Athens (Mythological character)1
- Medici, Alessandro de', 1510-15371