Former Owner
- Philadelphia Rare Books & Manuscripts Company1
- Philip Hofer1
- Philip Hurd1
- Philip van Alfen1
- Philippe Hurault de Cheverny1
- Phillip J. Pirages Fine Books & Manuscripts1
- Pierre Gélis-Didot1
- Québriac family1
- René Antoine Thoué1
- Robert H. Sayre1
- Robert Manning Strozier Library1
- Robert Williams1
- Rudolf Busch1
- Rush Hawkins1
- Ruth Cheney Streeter1
- Sabin1
- Saluti, Tomasso, active 20th century1
- Sam Fogg Rare Books & Manuscripts1
- Samuel Dennis1
- Samuel Whitaker Pennypacker1