Former Owner
- Mercantile Library Company1
- Meschatin La Faye family1
- Michael Wodhull1
- Michele Cavaleri2
- Michiel family1
- Mikhail Golitsyn1
- Millard Meiss1
- Milton Fischmann13
- Molin1
- Monasterium sanctorum quadraginta martyrum (Treviso Italy)1
- Moritz Joseph Johann von Dietrichstein1
- Morris H. Morgan5
- Morris Jastrow, Jr.1
- Murray Anthony Potter1
- Nathaniel Sherman Bouton1
- Nettie Goldsmith Naumburg1
- Niccolò Albergati1
- Nicolai Briganti1
- Nicolas Antoine Labbey de Billy2
- Nicolaus de Monte Murro1