Former Owner
- Joost Ritman1
- Joseph Anton Koch1
- Joseph Haslewood1
- Joseph Mayner1
- José Fernando Ramírez1
- Judith Lady Montefiore College1
- Julius Heinrich Jeidels1
- Julius de Cardelinis1
- Katholieke Universiteit te Leuven Universiteitsbibliotheek1
- Kloster Bredelar1
- Kloster Rebdorf1
- L. Paganthus1
- Lambach Abbey1
- Lancino Curti1
- Laura Hurd Motion1
- Leo Olschki1
- Leo S. Olschki Editore1
- Leonardus Martinotius1
- Leonhardus Cuntius1
- Leslie, John (c. 1840), bookseller1