Former Owner
- Mary Elizabeth Holte1
- Mary Lusher1
- Mary, Queen of Scots1
- Matteo Barresi1
- Matthew Bloxam1
- Matthew Simpson Parkhurst1
- Matthias Corvinus1
- Maurice Johnson1
- Maurice Kann1
- Mercantile Library Company1
- Michael Tomkinson1
- Michael Wodhull1
- Michaeliskonvent1
- Michel Chasles1
- Michel Ferdinand d'Albert d'Ailly1
- Michel Guibé1
- Michel de Léon1
- Middle Hill Rare Books & Manuscripts AB (Stockholm, Sweden)1
- Miguel de Mayora1
- Mikhail Golitsyn1