Former Owner
- Matthew Hale1
- Matthias Corvinus1
- Maurice Johnson1
- Maurice Kann1
- Maxwell Sommerville1
- Mayer Sulzberger1
- Mayfair Rare Books and Manuscripts1
- Melchior Daniel Neubronner1
- Menaḥem Naḥum, ha-Leṿi, mi-ḳ.ḳ. Dribin1
- Merlemont family1
- Meschatin La Faye family1
- Michael Kantakouzenos Şeytanoğlu1
- Michael Wodhull1
- Michel Chasles1
- Michel Ferdinand d'Albert d'Ailly1
- Michel Guibé1
- Michel de Léon1
- Michele Amari1
- Michiel family1
- Middle Hill Rare Books & Manuscripts AB (Stockholm, Sweden)1