Finally read an Agatha Christie! (I know I read Orient Express in elementary school but I don't really recall most of it, aside from my impression of Hercule Poirot and his long-winded explanations.) It's interesting to read about the problematic original title's change coming to the US, as well as the prolific effect Christie's story has had since publication. 
 Succinct and satisfying. For the record: I didn't guess the killer correctly.