Save this storySave this storySave this storySave this storyIn the seventeenth chapter of John Dickson Carr’s mystery novel “The Three Coffins” (1935), the story pauses so that Dr. Gideon Fell, a brilliant sleuth, can deliver the “Locked-Room Lecture,” an elaboration of all the various methods by which a person might be found murdered in a “hermetically sealed chamber,” a room locked from the inside. It’s one of the most justly celebrated passages in the history of detective fiction, and Carr, engaging the possibilities and limitations of genre as his very subject, breaks the fourth wall with merry aplomb.