Wealthy spinster Rachel Innes and her niece and nephew, Gertrude and Halsey, rent a country house called Sunnyside for the summer. Upon arrival, the butler reveals to them that he believes there’s a ghost in the house. During the first night, Rachel is roused from sleep by strange sounds. The next night she’s awakened by a revolver shot, and discovers a dead body at the foot of the house’s circular staircase. The investigation into the murder reveals the house and its owners, the Armstrong family, hold many secrets. The Circular Staircase was published in 1908 and is credited with pioneering the “Had I but known” school of mystery writing, a form of foreshadowing that hints at impending disaster through the narrator’s regrets of their actions. The novel was adapted as a silent film in 1915, and most notably as a hit Broadway play, “The Bat” in 1920. This book is part of the Standard Ebooks project, which produces free public domain ebooks.