Former Owner
- Latham family1
- Lathrop Colgate Harper2
- Laurence Claiborne Witten II2
- Laurent Campagne1
- Laurentius van der Torqel1
- Lawrence J. Schoenberg13
- Legoué1
- Leicester Harmsworth1
- Leo S. Olschki Editore8
- Leonardo Lapiccirella1
- Librairie Damascène Morgand1
- Libreria antiquaria Mediolanum1
- Libreria la Bibliofila1
- Libri, Edoardo, active 20th century1
- Lionel Tollemache, 4th Earl of Dysart1
- Lisa Norris Elkins1
- Little family1
- Llewelyn Lloyd-Mostyn, 3rd Baron Mostyn of Mostyn1
- Loftus Bland1
- Long Island Historical Society, Maine1