Former Owner
- Paul Sabatier1
- Peter Le Neve1
- Petrus Hofstede1
- Philadelphia Rare Books & Manuscripts Company1
- Philip C. Duschnes1
- Philip Hofer1
- Philip Kerr, 11th Marquess of Lothian1
- Phillip J. Pirages Fine Books & Manuscripts2
- Pierre Pithou1
- Pius XI1
- Poor Clares1
- Prince Augustus Frederick, Duke of Sussex1
- Québriac family1
- R. Stora and Company1
- Renzo Rizzi libri antichi1
- Robert Forrer1
- Robert Hoe III2
- Robert Lyle1
- Robert de Hangest1
- Rudolf Busch1