Former Owner
- Nonnberg Abbey1
- Octave Chavaillor1
- Oliver R. Barrett1
- Oric Bates1
- Otto Ege1
- Over, Watson1
- P. Pigeot1
- Paul Gottschalk1
- Paul Louis Feiss1
- Pease, John William, 1820-19001
- Petrus Jensenius1
- Petrus Leonardus1
- Petrus Martinotius1
- Petrus Ysermans1
- Philip Carteret Webb1
- Philippe de Béthune1
- Phillip J. Pirages Fine Books & Manuscripts1
- Pierre Fraenkel1
- Pierre de La Vacherie1
- Pietro1