The Circular Staircase

Rachel Innes, a middle-aged spinster, has barely settled in at the country house she has rented for the summer when a series of bizarre and violent events threaten to perturb her normally unflappable nature. A strange figure appears briefly in the twilight outside a window. At night, a rattling, metallic sound reverberates through dark halls, and — most disconcerting of all — the body of a strange man is found lying in a pool of blood at the bottom of a circular staircase.
Before this spine-tingling tales ends, five connected deaths shatter the normally placid atmosphere of the vacation retreat. Rachel's devoted niece and nephew are among the prime suspects in one of the murders; stolen securities and a bank default threatens the young pair's financial security; and Aunt "Ray" ultimately fights for her life in an airless secret room.
Author of more than 60 chilling mysteries, Mary Roberts Rinehart (1876–1958) is credited with inventing the "Had-I-But-Known" school of detective fiction, which typically involved an attractive heroine caught up in a seemingly endless succession of dangerous predicaments. The Circular Staircase

— originally published in 1908 — is considered the first of the genre. A clever blend of intrigue, villainy, and heart-pounding suspense, leavened with traces of wry humor, this immensely popular novel will delight today's crime fiction buffs as much as it galvanized readers almost 90 years ago.