Former Owner
- Mercantile Library Company1
- Merlemont family1
- Meschatin La Faye family1
- Michael Bernays1
- Michael Kantakouzenos Şeytanoğlu1
- Michael Krupp1
- Michael Wodhull1
- Michaeliskonvent1
- 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