From a British mystery author known as "the master of the whodunnit," an amateur sleuth searches for a source of poison-pen letters in an English village (The New York Times Book Review). The small town of Cotten Abbas is losing some of its quirky charm now that wealthy Londoners are moving there in droves. Needless to say, the locals are none too happy. But who among them is angry enough to send a series of anonymous letters,...