Crime fiction--a product of the burgeoning metropolis of the 19th century--features specialists who identify criminals to protect an anxious citizenry. Before detectives came to play the central role, the protagonists tended to be lawyers or other professionals. Major English writers like Gaskell, Dickens and Collins contributed to the genre--Fergus Hume's The Mystery of a Hansom Cab was a best-seller in 1887--and American and French authors created new forms. This book explores thematic aspects of 19th century crime fiction's complex history, including various social and gender roles between different time periods and settings, and the imperial elements that made Sherlock Holmes seem dynamically contemporary.