Unusual in that this is a classic village mystery but it is not a Miss Marple, it's a Hercule Poirot. A classic whodunit with Poirot brought in by Superintendent Spence to re-investigate the murder of Mrs. McGinty before the accused is hanged. There are multiple suspicious village inhabitants, a second murder, and an unforeseen and clever conclusion.
What I liked most about this one was the presence of Ariadne Oliver, who shows up in roughly six Poirot novels. She is a successful writer of detective fiction and Agatha Christie uses her to both satirize herself, and air her own grievances. Mrs. Oliver has created a successful Swedish detective who is a vegetarian. The public loves him, she cannot stand him. This mirrors Christie's own feelings about her most successful creation, Poirot.