Former Owner
- Lawrence J. Schoenberg4
- Leicester Harmsworth1
- Lewis L. Gould2
- Lisa Kiser3
- Louis Lucien Bonaparte1
- Luigi Celotti1
- M. Pierre Guarin1
- Mannheimer Hofbibliothek1
- Marie-François Duchesne de Beaumanoir2
- Martin Schøyen2
- Marvin-L. Colker1
- Mary Bloch1
- Mary Lacaita1
- Mary W. T. Dickinson1
- Mayer Sulzberger1
- Michael Greenberg1
- Mikhail Golitsyn1
- Milton Fischmann3
- Mirmellus Arnandi1
- Monasterio de El Paular1