Former Owner
- Peter Le Neve1
- Petrus Giraud1
- Petrus Hofman Peerlkamp1
- Petrus Hofstede1
- Petrus Molitor1
- Philadelphia Rare Books & Manuscripts Company1
- Philip C. Duschnes1
- Philip C. Duschnes Rare Books & First Editions1
- Philip Hofer2
- Philip Kerr, 11th Marquess of Lothian1
- Philippe de Béthune1
- Phillip J. Pirages Fine Books & Manuscripts1
- Pietro Odescalchi1
- Pius XI1
- Prince Augustus Frederick, Duke of Sussex4
- Québriac family1
- R. A. Godwin-Austen1
- R. F. Pain1
- R. Stora and Company1
- Raoul Léonor Lignerolles1