Former Owner
- Burndy Library4
- Bury St Edmunds Abbey2
- Buxheim Charterhouse6
- Byron Reed1
- Būtū ʻAbd al-Bāqī1
- C.B1
- Caesareum Societatis Jesu Collegium Viennense1
- Carl Hermann Grabauer1
- Carl Reinhardt4
- Carleton Rubira Richmond1
- Carlo Archinto, 2nd Marquess of Parona, 3rd Count of Trainate1
- Carlo Bonaparte1
- Carlo Morbio2
- Carlos José Gutiérrez de los Ríos y Rohan Chabot Fernán-Núñez1
- Catharine Wisser1
- Catherine Barton1
- Caxton Club1
- Cecil Deedes1
- Chapelle du monastère du Carmel de Nantes1
- Charles Alexander de Cosson1