Former Owner
- John Ives1
- John Morgan1
- John Peacock1
- John Read Dore1
- John Ruskin1
- John Topham1
- John Walker1
- John West, 1st Earl De La Warr1
- John Willis1
- John Wright2
- Joseph Barrois2
- Joseph E. Widener8
- Joseph H. Haines1
- Joseph Mayner1
- Josephine Widener Wichfield2
- Juan de Londono1
- Jān Sipār Khān ibn Rustamdilkhān1
- Karbalāʼī Muḥammad Ḥusayn Qāsimʹābādī1
- Karl Wilhelm Hiersemann8
- Katholieke Universiteit te Leuven Universiteitsbibliotheek1