The Shadow Knows aptly takes its title from the old radio mystery play that used to begin with a frightening voice saying, "Who knows what evil lurks in the hearts of men? The Shadow knows." The foregoing analysis suggests that there is plenty of evil in everyone's heart, even N.'s, but the vehicle Johnson uses for its presentation is a mixture of the detective novel, the Gothic romance, and the surreal fiction of Franz Kafka (whose best known protagonists are named "K.").

As one reviewer described the novel, it is like "Charlotte Bronte filtered through Kafka, or like a strange dream in which Agatha Christie is transformed into a feverish metaphysician."

Johnson uses many different devices to develop her fiction, chief among them the withholding of details after they have first been mentioned. For example, N. mentions Andrew's letter twice before revealing the...