Former Owner
- John Swyntoun1
- Joseph Anton Koch1
- Joseph Barrois21
- Joseph Whitney1
- Joseph-Félix Allard1
- José Antonio Conde1
- Juana I of Castile1
- Julius Hess1
- Jérôme Bignon1
- Kenneth Hyde1
- Kloster Bredelar1
- Lathrop C. Harper, Inc.1
- Laurence Claiborne Witten II3
- Laurentius van der Torqel1
- Leigh Baker1
- Leo S. Olschki Editore8
- Leonardo Lapiccirella2
- Libreria antiquaria Mediolanum1
- Libreria la Bibliofila2
- Libri, Edoardo, active 20th century1