(Spoilers - I talk about how much of the solution I figured out in detail, and I will be naming the killer and their plot.)
Once again, I have returned to a true classic in detective literature by John Dickson Carr. This time, it is one of his rare non-historical stand-alones, "The Emperor's Snuff-Box", which features neither Dr. Fell or H.M., nor Henri Bencolin. Instead we get a completely new detective: British expat and criminological psychologist Dr. Dermot Kinross. Kinross is a very interesting detective because he does not share the kind of eccentricities that Fell or Merrivale have; although he is an amazing sleuth, Kinross is surprisingly normal. We know that he has had facial reconstruction surgery after a bomb injury in war, and that he is very hard working and empathetic. He has to work alongside M. Aristide Goron, the French prefect of police in the beach town of La Bandelette who wears white roses in his suits, says words like "zizipompom" and also maybe unfairly intimidates suspects, when a very vexing (but not impossible) murder happens.
Our protagonist is Eve Neill. Recently she has gotten divorced from her abusive husband Ned Atwood, and now that he has left she has become engaged to her across-the-street neighbor Toby Lawes. Toby lives with the rest of his family - his sister Janice, his parents Sir Maurice and Lady Helena, and his uncle Ben Phillips. Maurice happens to have a large collection of historical trinkets. Of course, this perfect match is challenged when Ned returns to La Bandelette to win Eve back from Toby. One night, after Eve and the Laweses (sans Sir Maurice) return from a Shaw play, Ned barges in on Eve in her bedroom - he still has a house key. They begin to argue, with Ned threatening to pull back the windows so that Sir Maurice can see the hubbub from his second-floor study where he houses his antiques. Ned sees Maurice there looking at his newest item, a snuff-box once belonging to Napoleon I, but Eve turns the lights off and then Toby calls. After an excruciating telephone conversation, Eve and Ned turn back to the window to see a gloved hand turn of the main light of Sir Maurice's study - and across the room illuminated by desk-lamp, Sir Maurice with his head bashed in and his precious snuff-box shattered into a million pieces. As if this wasn't bad enough, Ned then falls down the stairs with a concussion (he eventually slips into a coma causing his testimony to become obsolete), Eve is locked out of her own house (she suspects her nosy maid Yvette) and the police find a shard of the snuff-box on her clothing. While Goron and the French police all close in on poor Eve Neill, Dr. Kinross in her only hope as he tries to use his psychological insight to prove an alternate theory - that the killer may just be a Lawes...
The writing here is quite excellent. I read this whole thing in two days (it is rather short for a Carr) and was never bored. Even the parts where I thought I would be bored, like the Laweses conversing, or Eve talking with Yvette's sister Prue, were page-turning. His descriptions of the French seaside village and the daily life there is excellent. He also paints some of the characters brilliantly - we get a great insight into Eve's femme fatale identity, Ned's cunning charisma, Toby's boyishness, Goron's eccentricity, and Kinross' subtle personality which is perhaps described the best. Unfortunately, some of the other characters, like the other Lawes family members and the help, are more one-dimensional characters.
The puzzle here is really well plotted. There seem to be only a few clues, none of which really make much sense - the smashed snuff-box, a necklace worn by Marie Antoinette's favorite which is found discarded on the floor but intact, the brown gloves, the lights in Sir Maurice's study, the shard on Eve's nightgown, and most importantly the testimony of Eve and the incapacitated Ned. These things all seem to have no explanation, but Dr. Kinross perfectly puts them together into one surprising but logical solution.
Now for the spoilery stuff. I will admit I half-solved this, which is very rare for me with Carr (the only other time I got close was when I figured out who the killer was in He Who Whispers but discarded the theory for being a bit too far-fetched - it wasn't.) To put it simply, I knew that when Ned told Eve that he saw Sir Maurice looking at the snuff-box from across the street, that he was lying. It seemed obvious to me that he couldn't have known it was a snuff-box - it was too far away and it looked like a watch. While this made me suspect him seriously, I still didn't know how he did it. My fatal flaw was thinking that a.) Ned has still seen Sir Maurice alive at his "sighting" and b.) Brown-Gloves was the killer. My only explanation was that with the lights off, Ned somehow slipped away and stole into the Lawes house with his key...? It made absolutely no sense and eventually my theory fell apart, although Ned was still suspect in my mind. But when Dr. Kinross accused Toby of being Brown-Gloves, well, I won't say it utterly surprised me (I've seen too many fiances of the main female character be the murderer in different authors' books to not suspect Toby) but the evidence of saying he saw the study lights on when he couldn't have because of the rug caught me off-guard. And so, for one glorious chapter, I completely disregarded Ned and got sucked into the long and short of the Toby theory. Even when Toby told the truth, I was still dazed. And when Ned was finally reintroduced as the killer, it may not have been shocking, but still the kind of surprise that made me go "I should have known all along." My simply error in thinking that Maurice hadn't been killed before Ned "saw" him fiddling with the snuff-box cost me my mostly correct theory (I even caught onto the motive - the whole McConklin story seemed to important to disregard.) And the beginning of that second chapter - now if that isn't daring! Saying that his "mistake" was saying he'd win back Eve at the hotel... not because he was afraid of gossip but because it was the genesis of his having to kill Sir Maurice in the first place! He "wasn't afraid" of Sir Maurice hearing him on the street not because he knew he was deaf, but because he knew he was dead! It borders so closely on being unfair in retrospect but it really is well done.
Overall I thoroughly enjoyed this outing from John Dickson Carr. My only gripes were that some of the characters were too flat, there is still some misogyny in Eve's character although she is at least shown as a victim and not "asking for it" or anything, and if you've read too many murder mysteries like me, the killer's identity can be easy to glom onto - although even I was blindsided when I had half the solution laid out in my head!