Former Owner
- John Cochran1
- John Dozier Gordan1
- John Eliot Hodgkin1
- John Estmond1
- John Hope, 1st Marquess of Linlithgow1
- John Ives1
- John Walker1
- John West, 1st Earl De La Warr1
- Joost Ritman1
- Katholieke Universiteit te Leuven Universiteitsbibliotheek1
- Klaus Dieter Dahmen1
- Lambertus Eerens1
- Laurent Campagne1
- LeMare1
- Legoué1
- Leonardus Martinotius1
- Lepeletier de Rosanbo1
- Leslie, John (c. 1840), bookseller1
- Library of the Dominicans of Paris1
- Louis Bourguet1