Crooked House by Agatha Christie
My rating: 3 of 5 stars
Another quiet mystery - there are two poisonings, and one attempted head-bashing, but mostly this is the story of a man, in love with a woman, trying to help figure out who is killing members of her family. Charles' father is Head of Scotland Yard and gives Charles permission (his blessing?) to go to Three Gables and help the police determine who had poisoned Sophia's grandfather. Virtually every one in the house is under some suspicion, and a few of the candidates appear too good to be true. The actual poisoner is pretty obvious, if only because Charles' father gives him an explicit description (which, of course, Charles ignores).
This isn't a Poirot or a Marple, so Ms. Christie can allow herself a little freedom from the confines of those worlds. Her best (IMVHO) is And Then There Were None, and this mystery doesn't come close in terms of suspense and puzzle.