I didn’t know anything about Bernard Capes before reading this, only that this was a reissue of a Golden Age crime fiction book, much in the same line as the British Library Crime Classics. Good enough for me, at least when I’m in the mood to tune out and just read an old-timey mystery: this pretty much delivered on that, though it’s hardly the most original or the most exciting of that line I’ve read.
It actually takes a long time for the story to explain why it’s The Mystery of the Skeleton Key; at times, I was actually tempted to check the right book was inside that slipcover! After a long preamble involving some of the characters meeting in Paris, and a bit of mystery about a Baron who plays chess for half-a-crown and frequents the oddest places, eventually there is actually a murder to be investigated. The wrong people are accused, the timings are all mixed up, and the son of the house (because if it’s not quite a country house mystery, it’s definitely set in a country house) is implicated because the girl who gets murdered — killed with a shot from his gun — was pregnant with his child.
In the end, the solution relies on coincidence, spurious old-fashioned science (a man inherits an injury-induced mannerism from his father due to the fact that his mother saw his father with the injury while pregnant with him), and various people not being quite who/what they say they are. I think it’s actually quite interesting in terms of who the culprit turns out to be — not a common solution, and against Knox’s Ten Commandments in a sense — but otherwise there’s not much to set it apart, and in tone it’s fairly dry and without any sense of urgency. My main feeling was mild curiosity, and that’s about it. Nothing terrible, but nor is it something I’d recommend.