A locked-room mystery is a story about the solving of a crime, usually murder, that appears impossible to have been committed. The crime need not have taken place inside a locked room but in any utterly inaccessible place, such as in a field of pristine snow.
Published in April 1841, Edgar Allan Poe’s “The Murders in the Rue Morgue” was the first American locked-room mystery story. Two women, a mother and daughter, are heard screaming. Neighbors break in to find them savagely murdered in their locked apartment with no secret passages or loose floorboards.
The story continues to baffle readers today, more than a century later, just as a magician continues to baffle an audience. The difference is that in the denouement of the story, the brilliant detective, C. Auguste Dupin, shows up the official police by telling us the who and how of the crime, whereas a magician never raises the curtain to reveal the illusion.
This mystery subgenre reached its height of popularity between the two World Wars. If you’re looking for a classic locked-room mystery, read John Dickson Carr’s THE THREE COFFINS. If you’re looking for an historical mystery in the locked-room tradition, read my own Miriam bat Isaac adventure, THE DEADLIEST SPORT.