Agatha Christie’s Murder in Mesopotamia is a Hercule Poirot mystery with a non-Poirot first-person narrator, Amy Leatheran, a nurse engaged to keep a nervous archaeologist’s wife company. Her patient has been receiving threatening letters signed with her dead first husband’s name, and when she turns up dead, suspicion falls on the other members of the archaeological dig.
I’d read this one years ago, too young to realize how implausible the last twist of the ending is. Worse, it’s unnecessary; it would have been a much more interesting book without it. Well, at least Nurse Leatheran is a sensible person to spend time with.