Former Owner
- Mario Maffei1
- Marion Lawrence1
- Martin Breslauer1
- Mary Stanley, Countess of Derby1
- Mary, Queen of Scots1
- Mathias Schurer1
- Matthew Bloxam1
- Matthew Simpson Parkhurst1
- Maurice Johnson1
- Mayer Sulzberger1
- Mercantile Library Company1
- Michaeliskonvent1
- Monastero di Santo Spirito in Verona1
- Moritz Dessauer1
- Morot1
- Mrs. E.J. Hooper1
- Muḥammad Dhará1
- Muḥammad Riz̤ā1
- Muṣṭafa Ṣidḳī1
- Muṣṭafá Ṣidqī1