JessFirst to rec
“John Dickson Carr was a man with a mission: writing as many "impossible crime" mysteries as possible. He did such a good job that he had to publish some of his books as Carter Dickson, since his publishers thought he would flood the market if he released them all as himself.
The classic impossible crime is a murder committed in a room that's locked from the inside, but Carr invented a huge number of variations on the theme. In one case, a murder is committed on a snowy street with no footprints nearby. In another, the police have every exit from the room under observation. Watching him explore the limits of the form is super fun!
While Carr has three main series detectives, there's no meaningful continuity between novels. You can read them in any order. However, each detective has a slightly different flavor. The Bencolin novels are gothic and baroque, the Fell mysteries typically explore tight communities, and the Merrivale stories are fast-paced and often funny.
If you're looking for a place to start, consider these classics: The Judas Window (Merrivale), The Three Coffins (Fell), or The Waxworks Murder (Bencolin).
Fun fact: The Three Coffins has an extended monologue by Dr. Fell that lays out Carr's approach to impossible crimes. Carr ends up using basically all the tricks he describes across his various novels, and yet I very rarely see the solution before he reveals it!”