Former Owner
- Maxwell Sommerville1
- Mayer Sulzberger5
- Mayfair Rare Books and Manuscripts1
- Mazliah Finzi1
- Maḥmūd al-Ustādār, d. 1396 or 71
- Maḥmūd bin Nāṣir1
- Maḥmūd ibn al-Shaykh al-Fattāḥ1
- McCormick Theological Seminary1
- Medingen Abbey1
- Melchior Daniel Neubronner1
- Melk Abbey2
- Menaḥem Naḥum, ha-Leṿi, mi-ḳ.ḳ. Dribin1
- Menno Hertzberger1
- Mercantile Library Company1
- Merlemont family1
- Meschatin La Faye family1
- Messieurs Du Trieu2
- Michael Bernays1
- Michael Greenberg5
- Michael Kantakouzenos Şeytanoğlu1