For years, I’ve enjoyed reading and rereading my collection of Agatha Christie mystery stories. I’ve never bothered to count them, but they completely fill three 30-inch shelves in my bookcase, and it takes months to work my way through the entire collection. At the time they were written, mostly during the first half of the last century, they represented upper-class life in England fairly accurately. This was the world that Agatha Christie lived in and knew best. There were country manor houses with butlers, housemaids, valets and chauffeurs.