Former Owner
- Medingen Abbey1
- Mercantile Library Company1
- Michael Tomkinson1
- Michael Wodhull1
- Michaeliskonvent1
- Michel Chasles1
- Michel Ferdinand d'Albert d'Ailly1
- Michel Guibé1
- Michel de Léon1
- Michele Amari1
- Middle Hill Rare Books & Manuscripts AB (Stockholm, Sweden)1
- Miguel de Mayora1
- Mikhail Golitsyn1
- Millard Meiss1
- Milt Freudenheim1
- Milton S. Carothers1
- Minerva Kaiser1
- Minnis, Katherine1
- Molin1
- Monasterium sanctorum quadraginta martyrum (Treviso Italy)1