- Little office of the Blessed Virgin Mary (Catholic Church)1
- Liturgical books4
- Liturgics73
- Manuscript fragments6
- Manuscript waste2
- Manuscripts41
- Manuscripts, Dutch10
- Manuscripts, English (Middle)1
- Manuscripts, French13
- Manuscripts, German1
- Manuscripts, Italian2
- Manuscripts, Latin13
- Manuscripts, Latin (Medieval and modern)122
- Manuscripts, Medieval94
- Manuscripts, Renaissance2
- Marginalia1
- Mary, Blessed Virgin, Saint4
- Massachusetts--Boston35
- Massachusetts--Northampton2
- Massachusetts--Wellesley7