Former Owner
- Peter Arrell Brown Widener2
- Peter Arrell Brown Widener II2
- Peter Eaton2
- Philip Augustus Hanrott2
- Philip Kerr, 11th Marquess of Lothian2
- Pierleone Leoni2
- Pierre Gélis-Didot2
- Pierre Pithou2
- R. Stora and Company2
- Rabbinical Seminary Vienna2
- Richard Gough2
- Robert Mignan2
- Rosamond B. Loring2
- Ross Winans2
- Rudolf Busch2
- Sam Fogg Rare Books & Manuscripts2
- Samuel Whitaker Pennypacker2
- San Pietro Apostolo2
- San Sisto, Piacenza2
- Sandbergs Bokhandel2