Asimov's Mysteries by Isaac Asimov (1968)
Isaac Asimov may be best known as a science fiction and popular science writer, but he liked to wander out into other literary fields from time to time–often ones that he wasn't very good at. The mystery genre had obvious attractions for Asimov with its puzzles and simple prose conventions very similar to science fiction and from time to time he'd put aside his robots and psychohistorians, pick up his magnifying glass, and try to craft a whodunnit.
Asimov's Mysteries is a collection of 14 mystery short stories penned by Asimov between 1939 and 1967. They're a mixed bunch. Ostensibly an anthology of science fiction mysteries, some are not mysteries, some are not science fiction, some are straight mysteries pretending to be science fiction, and some are just extended jokes. In other words, it's about as consistent as any later anthology of Asimov made up of stories written over three decades.
Most of the stories revolve around Dr Wendell Urth, an "extraterrologist" and extreme agoraphobic who never leaves his flat and is obviously Asimov's attempt at reinventing Rex Stout's homebody detective, Nero Wolfe. As is usual in the mystery story, the plots revolve around puzzles of murder with one red herring thrown in and, save in one case that isn't a mystery, a neat solution at the end. As is typical with Asimov, the mysteries are generally logic problems which he dresses up with grander science fiction ideas that are really overstuffed McGuffins played out by flat characters who never develop any individuality, much less anything more profound.
It's all very fluffy stuff and wouldn't matter except for Asimov's maddening dislike for rewriting that leaves his stories sloppy and filled with all sorts of holes that he gets away with only because they never occur to him in the first place. Asimov never grasped that a successful story needs to be not just a logic puzzle, but a logical story that needs to be honed and polished until the conclusion is inevitable from a dramatic point of view as well as from the crossword puzzle point of view. What a sci fi story can forgive, the mystery cannot, which just goes to show that mixing two genres is more than mixing tropes, but rather of adapting one genre to the demands of another.
That's one mystery that Dr Asimov never solved.