Former Owner
- Magby, H1
- Mannheimer Hofbibliothek1
- Marcantonio Contarini1
- Marcantonio V Borghese1
- Marcela Gabriela1
- Marchese Linterno1
- Marchese Porri-Carcani1
- Marco Antonio Morosini1
- Maria Ludovica Favia del Core Borromeo1
- Marie Cleophe de Sollario1
- Marie de Albano1
- Mario Maffei1
- Martin Breslauer1
- Matteo Barresi1
- Mayfair Rare Books and Manuscripts1
- Mazliah Finzi1
- Melk Abbey1
- Mercantile Library Company1
- Michael Bernays1
- Michael Tomkinson1