Former Owner
- Nancy McGrath2
- Nettie Goldsmith Naumburg1
- Nicholas B. Scheetz1
- Norman H. Strouse1
- Oliver Henry Perkins2
- Oliver R. Barrett1
- Otto Ege32
- Otto Orren Fisher1
- P. Pigeot1
- Parroco di Taviano, Luigi Bruno, active 20th century1
- Paul Durrieux1
- Paul Gottschalk1
- Paul Louis Feiss1
- Peter Arrell Brown Widener2
- Peter Arrell Brown Widener II1
- Peter Le Neve1
- Petrus Hofstede1
- Petrus Jensenius1
- Petrus Ysermans1
- Philadelphia Rare Books & Manuscripts Company1