Former Owner
- J. & J. Leighton1
- J. Meade Falkner1
- James Ley, 1st Earl of Marlborough1
- James Tanis1
- Joachim Guerrinus de Montefegatesio1
- Johannes Abezier1
- Johannes Vivianus1
- Johannes de Helb1
- John Fletcher Hurst1
- John Henry Ellis1
- John Josias Conybeare1
- John Roland Abbey1
- Julia Burgess1
- Julius Heinrich Jeidels1
- Julius de Cardelinis1
- Katherine Somerset Wyttenbach Fenwick1
- Katholieke Universiteit te Leuven Universiteitsbibliotheek1
- Laura Hurd Motion1
- LeMare1
- Lepeletier de Rosanbo1