Former Owner
- Marvin-L. Colker1
- Mary Bloch1
- Mary Schell Collins1
- Mary, Queen of Scots1
- Maurice Kann1
- Mayfair Rare Books and Manuscripts1
- Merlemont family1
- Meschatin La Faye family1
- Michel de Léon1
- Middle Hill Rare Books & Manuscripts AB (Stockholm, Sweden)1
- Mikhail Golitsyn1
- Minerva Kaiser1
- Minnis, Katherine1
- Mirmellus Arnandi1
- Monsieur de Bel Air1
- Morton Davis Mitchell1
- Mrs. F. W. Bartlett1
- Muriel Agnes Fry1
- Museo Cavaleri1
- N. Pauli1