Former Owner
- Lehn of Denmark1
- Leicester Harmsworth1
- Leigh Baker1
- Lew David Feldman2
- Louis H. Silver1
- Luigi Celotti2
- Lundell Library1
- Madeleine Cosman1
- Maggs Bros Ltd1
- Mantell1
- Marco Antonio Morosini1
- Marguerite de Belleville1
- Mark Lansburgh1
- Marsden J. Perry1
- Martin J. Cooper4
- Mary Talbot, Countess of Shrewsbury1
- Miriam Lutcher Stark6
- Miss Gostling1
- Morell Thurston1
- Mortimer Loeb Schiff1