Former Owner
- Juan Antonio de la Reguera1
- Juan Rodriguez1
- Juana I of Castile1
- Julian I. Edison1
- Julius Heinrich Jeidels1
- Justin MacCarthy Reagh1
- Jón Þorstensson1
- Kang Youwei1
- Karl Hermann Berendt1
- Katharinenkirche, Nuremberg1
- Katherine Somerset Wyttenbach Fenwick1
- L. Paganthus1
- Lambach Abbey1
- Lathrop C. Harper, Inc.1
- Laurent Campagne1
- Legoué1
- Leo Olschki1
- Leopold Gruber1
- Libreria antiquaria Mediolanum1
- Libreria la Bibliofila1