K. is a crime novel by the American writer Mary Roberts Rinehart (1876-1958) set in post-Victorian era Allegheny, Pennsylvania, which has been a part of the city of Pittsburgh since 1907.The novel tells the story of Sidney, who takes in a boarder with the initial K. and whose presence leads to mystery.Ms Rinehart is considered the American Agatha Christie. Rinehart invented the phrase "the butler did it", and wrote hundreds of short stories, plays, travelogues and special interest articles. K is a romance set in the industrial Victorian era. When Sidney takes in a border with the initial "K", her life becomes entwined with the mystery surrounding "K". Lies and intrigue surround Sidney.