File No. 113, published in 1867, is a foundational detective novel by Émile Gaboriau, a pioneer of French crime fiction. The story centers on Monsieur Lecoq, an astute and methodical detective investigating a mysterious bank robbery and murder. With its intricate plotting, multiple layers of deception, and an emphasis on logical deduction, the novel helped shape the genre’s conventions and influenced writers like Arthur Conan Doyle. Gaboriau’s portrayal of criminal psychology and procedural detail marks File No. 113 as an important precursor to the modern detective story.
