Former Owner
- Michael Wodhull1
- Michaeliskonvent1
- Michel de Léon1
- Michele Amari1
- Middle Hill Rare Books & Manuscripts AB (Stockholm, Sweden)1
- Mikhail Golitsyn1
- Millard Meiss1
- Minerva Kaiser1
- Minnis, Katherine1
- Mirmellus Arnandi1
- Molin1
- Monsieur de Bel Air1
- Morton Davis Mitchell1
- Mrs. F. W. Bartlett1
- Mrs. Turnbull1
- Muriel Agnes Fry1
- Murray Anthony Potter1
- Museo Cavaleri1
- Muḥammad ʻAbduh1
- Muḥammad Ṣābir1