Former Owner
- Lady Margaret Ayloffe1
- Lambertus Eerens1
- Lathrop Colgate Harper1
- Laurence Kirby1
- Laurent Campagne1
- Legoué1
- Leo Olschki1
- Leo S. Olschki Editore2
- Libri, Edoardo, active 20th century1
- Lisa Norris Elkins1
- Louis Bourguet1
- Louis César de La Baume Le Blanc2
- Lutheran Theological Seminary at Philadelphia1
- Lydia Thompson Morris1
- Maggs Bros Ltd6
- Maksymilian Mielzynski1
- Marchese Porri-Carcani1
- Margaret F. Woodward1
- Margaret Le Seigneur1
- Margaret of Croy1