Books about Detective and mystery stories (sorted alphabetically)
- Leavenworth Case Anna Katharine Green
- Lerouge Case Emile Gaboriau
- Library of the World's Best Mystery and Detective Stories
- Lighted Way E. Phillips Oppenheim
- Lock and Key Library: Classic Mystery and Detective Stories: Old Time English
- Lock and Key Library: Classic Mystery and Detective Stories: Old Time English
- Lock and Key Library: The most interesting stories of all nations: American
- Lock and Key Library: The Most Interesting Stories of All Nations: American
- Lock and Key Library: The Most Interesting Stories of All Nations: North Europe — Russian — Swedish — Danish — Hungarian
- Lock and Key Library: The Most Interesting Stories of All Nations: Real Life
- Locked Doors Mary Roberts Rinehart
- Lodger Marie Belloc Lowndes
- Lone Inn: A Mystery Fergus Hume
- long arm of Fantômas Pierre Souvestre and Marcel Allain
- Longsnozzle Event Hal Annas
- Lord John in New York C. N. Williamson and A. M. Williamson
- Lord Peter views the body Dorothy L. Sayers
- Lost Leader E. Phillips Oppenheim
- Lost Man's Lane: A Second Episode in the Life of Amelia Butterworth Anna Katharine Green
- Lost Parchment: A Detective Story Fergus Hume
- Lost Sir Massingberd: A Romance of Real Life. v. 1/2 James Payn
- Lost Sir Massingberd: A Romance of Real Life. v. 2/2 James Payn
- Loudwater Mystery Edgar Jepson
- Loudwater Tragedy T. W. Speight
- Love and hatred Marie Belloc Lowndes