Former Owner
- Lathrop C. Harper, Inc.1
- Lathrop Colgate Harper1
- Laurence Kirby1
- Laurent Campagne1
- Lawrence J. Schoenberg4
- Legoué1
- Leo Olschki1
- Leo S. Olschki Editore2
- Lewis L. Gould8
- Librairie Damascène Morgand1
- Libri, Edoardo, active 20th century1
- Lima Public Library3
- Linda Ehrsam Voigts2
- Lisa Kiser4
- Lisa Norris Elkins1
- Long Island Historical Society, Maine1
- Louis Bourguet1
- Louis César de La Baume Le Blanc3
- Louis XIV of France1
- Lutheran Theological Seminary at Philadelphia1