Mary Roberts Rinehart often called the American Agatha Christie, although her first mystery novel was published 14 years before Christie's first novel in 1922. Rinehart is considered to be the source of the phrase "The butler did it" from the novel "The Door," although not mentioned in the same way. Rinehart is also considered to have invented the "Had-I-But-Known" school of mystery writing, with the publication of The Circular Staircase.