The Police Agent (1867) is a milestone in the development of crime fiction. Its eponymous hero, the cunning Mr. Porion, a.k.a. PEre Cinnamon, does not employ his detective skills to pursue a vampire-like serial killer intent on bleeding children, but rather to protect him, while simultaneously serving other predatory aristocratic interests, such as providing the lecherous King Louis XV with a steady supply of virgins.

This crime novel Ponson du Terrail wrote may seem eccentric to 21st century eyes because the genre has undergone many refinements, but it remains fascinating as an...