Former Owner
- Mary W. T. Dickinson6
- Mary, Queen of Scots1
- Mathias Schurer1
- Matteo Luigi Canonici3
- Matthew Bloxam1
- Matthew Donadski1
- Matthew Simpson Parkhurst1
- Maurice Johnson1
- Mayer Sulzberger2
- Menno Hertzberger1
- Mercantile Library Company1
- Meschatin La Faye family1
- Messieurs Du Trieu2
- Michaeliskonvent1
- Michel Chasles1
- Milton Fischmann9
- Monastero di Santo Spirito in Verona1
- Moritz Dessauer1
- Morot1
- Mrs. E.J. Hooper1