Former Owner
- Marie Ange-Toussaint Placide de Ferron1
- Marilyn Carbonell1
- Marion H. Gottfried1
- Marion Lawrence1
- Martinus Nijhoff1
- Mary Elizabeth Holte1
- Mary Schell Collins1
- Mary W. T. Dickinson2
- Mary, Queen of Scots1
- Marymount College, Tarrytown2
- Merlemont family1
- Messieurs Du Trieu2
- Michel Chasles1
- Middle Hill Rare Books & Manuscripts AB (Stockholm, Sweden)1
- Milton Fischmann3
- Minnis, Katherine1
- Miriam Lutcher Stark2
- Monsieur de Bel Air1
- Morot1
- N. Pauli1