The Circular Staircase

by Mary Roberts Rinehart

"The Circular Staircase" by Mary Roberts Rinehart is a mystery novel published in 1908. When Rachel Innes rents a country house for the summer with her niece and nephew, she encounters mysterious intruders, unexplained noises, and a murder at the bottom of the titular staircase. As bodies accumulate and secrets multiply, Rachel must untangle a web of hidden identities, missing money, and family betrayals. This pioneering work established the "had I but known" mystery formula and became Rinehart's first bestseller.