Two reclusive sisters. A crumbling mansion. A dead doppelgänger. The final novel from the bestselling author known as the American Agatha Christie.

The Birches was one of the grand mansions of the 1920s, with a ballroom, tennis courts, and, of course, a swimming pool. But after the crash of '29, when Lois and Judith's father killed himself to escape his debts, the family turned the summer home into a fulltime retreat from the world. Decades later, Judith is the queen of New York society, a fast-living beauty whose nerves are beginning to fray, while Lois still lives in the dilapidated old mansion, writing mystery novels to pay the bills. She is about to encounter a mystery of her own.

To stave off a nervous breakdown, Judith moves in with her kid sister. Terrified of an unnamed threat, she nails her windows shut and locks the door. Soon, a woman is found dead in the pool—a stranger who bears a shocking resemblance to Judith. In a family with a history of tragedy, a chilling new chapter is about to be written.

The Swimming Pool was the last of over forty novels published by Mary Roberts Rinehart over the first half of the twentieth century.