Former Owner
- Johannes Patou1
- John A. Savage Jr.1
- John D. Stanitz1
- John Dozier Gordan1
- John Eliot Hodgkin1
- John Estmond1
- John Ives1
- John Lee1
- John McRay1
- John Roland Abbey1
- John Ruskin1
- Joseph E. Widener1
- Lathrop Colgate Harper1
- Laurence William Hodson1
- Leo Olschki1
- Ludwig Rosenthal1
- Luigi Arrigoni1
- Maksymilian Mielzynski1
- Mannheimer Hofbibliothek1
- Marchese Linterno1