Though she owned several houses, Agatha Christie had one surpassing favorite: Greenway, on the Dart estuary in Devon. She was born nearby, bought it in 1938, and spent all her summers there until her death in 1976. It was, she wrote, "the loveliest house in the world." Greenway makes a thinly disguised appearance in at least two of her novels, and nearby settings also play a crucial role in her books. This book explores and illustrates the significance...