Former Owner
- Marino Grimani1
- Martin Breslauer1
- Mary Lacaita1
- Mathias Schurer1
- Matthias Corvinus1
- Maurice Kann1
- Mayfair Rare Books and Manuscripts1
- Mercantile Library Company1
- Meschatin La Faye family1
- Michael Wodhull1
- Michiel family1
- Mikhail Golitsyn1
- Millard Meiss1
- Molin1
- Monasterium sanctorum quadraginta martyrum (Treviso Italy)1
- Moritz Joseph Johann von Dietrichstein1
- Morris Jastrow, Jr.1
- Murray Anthony Potter1
- Nettie Goldsmith Naumburg1
- Niccolò Albergati1