First serialized in 1907 and then published as a book in 1908, Mary Roberts Rinehart's The Circular Staircase is the popular mystery story about the dowager Rachel Innes as she reveals and prevents a series of strange crimes at the home she has rented for the summer. The Circular Staircase was Rinehart's first bestseller and was the originator of the popular "had I but known" genre of mystery writing, where the main character narrates the tale and foreshadows impending doom and tragedy while reflecting on what they might have done differently if only they had known what was to come. Rinehart was inspired to write this tale after visiting a Gothic revival castle in Virginia and sets her story in a similarly mysterious old house in the country. The main character, Rachel, is an older woman who has raised her niece and nephew, who are now adults and have convinced her to leave her city home behind for the summer and vacation with them in the country. What follows is a masterfully written and suspenseful tale of murder, arson, kidnapping, and mysterious intruders sneaking about in the night that continues to thrill readers over a century later.