The Big Bow Mystery (1892)

A lodger is discovered dead behind a secured door in London’s East End, and the public soon joins the argument over how it happened. Zangwill’s short novel combines a durable impossible-crime problem with satire of the surrounding people and institutions. Particularly appealing if you want economy in the central idea but enjoy Victorian comic digressions. Avoid plot summaries: even a casual discussion of its historical influence can spoil the discovery.