Former Owner
- Mary W. T. Dickinson1
- Mary, Queen of Scots1
- Matthias Corvinus1
- Maurice Kann1
- Maxwell Sommerville1
- Mayer Sulzberger1
- Menno Hertzberger1
- Merlemont family1
- Michael Tomkinson1
- Michel Chasles1
- Middle Hill Rare Books & Manuscripts AB (Stockholm, Sweden)1
- Minnis, Katherine1
- Mitchell Starrett Buck1
- Monsieur de Bel Air1
- Morot1
- Morris Harold Saffron1
- Morton Davis Mitchell1
- Mrs. F. W. Bartlett1
- Muriel Agnes Fry1
- Museo Cavaleri1