Former Owner
- Maurice Kann1
- Mayfair Rare Books and Manuscripts1
- Menno Hertzberger1
- Mercantile Library Company1
- Merlemont family1
- Meschatin La Faye family1
- Michael Greenberg5
- Michael Tomkinson2
- Michael Wodhull1
- Michaeliskonvent1
- Michel Chasles1
- Michel Ferdinand d'Albert d'Ailly1
- Michel Guibé1
- Michel de Léon1
- Michele Cavaleri2
- Michiel family1
- Mikhail Golitsyn1
- Millard Meiss1
- Milton Fischmann24
- Minerva Kaiser1