Mildly entertaining British crime fiction from 1929. There's a bit more psychology than in Agatha Christie, but it's still ever so twee. A bunch of guests gather at a creepy country mansion with an ominous coat of arms. Foreigners and anyone who is "swarthy" are naturally suspect.
Albert Campion, who became her most famous character, makes his first appearance. He puts one in mind of Bertie Wooster but is nowhere near as funny. There is a nice twist at the end, with a darkly tragic backstory, but all that charging into the next room with a revolver is wearisome. I would recommend this only for deep fans of the genre.