City mysteries
City mysteries are a 19th-century genre of popular novel, in which characters explore the secret underworlds of cities and uncover corruption and exploitation.
The "mysteries" originated with the wildly successful serial novel The Mysteries of Paris by Eugène Sue, which had many imitators and lent the genre its name. The novels were usually first serialized in newspapers, and were held the title of fiction bestseller until unseated by Uncle Tom's Cabin.