Former Owner
- Nasir al-Din al-Tusi1
- National Library of Greece1
- New York Academy of Medicine2
- Nicholas N. Martinovitch1
- Nicolai Briganti1
- Nicolas Antoine Labbey de Billy1
- Nicolas Moreau1
- Nicolaus de Monte Murro1
- Norman H. Strouse1
- Norza, Leon1
- Nūr al-Dīn Darvīsh2
- Oettingen-Wallerstein library1
- Okar, Baganbhaṭṭa1
- Oliver R. Barrett2
- Oric Bates2
- Otto Ege2
- Otto Jahn1
- Otto Orren Fisher1
- Otto Vollbehr2
- Owen D. Young1