Former Owner
- Phillip J. Pirages Fine Books & Manuscripts1
- Pierleone Leoni1
- Pierre Pithou1
- Pietro Antonio Maffei1
- Pietro Girometti1
- Pius VI1
- Prediger (Schwäbisch Gmünd)1
- Prospero Caffarelli1
- R. Tolentino1
- Ramsau Monastery1
- Raoul Chandon de Briailles1
- Raoul Léonor Lignerolles1
- Richard McKeon1
- Robert Brodhead Honeyman1
- Robert Garrett1
- Robert Rossiter Hutton1
- Robert Samuel Turner1
- Roy G. Fitzgerald1
- Royal Monastery of Saint Mary of Guadalupe1
- Rudolf Busch1