Former Owner
- Julie Florence de Cossette1
- Julie de Busnel1
- Julius Heinrich Jeidels1
- Julius Hess1
- Julius de Cardelinis1
- Justin MacCarthy Reagh1
- Jérôme Bignon1
- K-L1
- K. B. Starkie1
- Karen L. Gould28
- Karl Anton, Prince of Hohenzollern1
- Karl F. Morrison2
- Karl Leopold Strauven1
- Karl Theodor Völcker's Verlag Und Antiquariat3
- Karl Wilhelm Hiersemann8
- Kartause Erfurt2
- Katherine Petersen1
- Katherine Somerset Wyttenbach Fenwick8
- Katholieke Universiteit te Leuven Universiteitsbibliotheek1
- Keith Jarvis4