The Man Who Knew Too Much is a book of detective stories that contains eight connected short stories about "The Man Who Knew Too Much", and unconnected stories featuring other heroes/detectives.

Horne Fisher, "The Man Who Knew Too Much", is the main protagonist of the first eight stories. In the final story, "The Vengeance of the Statue", Fisher notes: "The Prime Minister is my father`s friend. The Foreign Minister married my sister. The Chancellor of the Exchequer is my first cousin." Because of these intimate relationships with the leading political figures in the land, Fisher knows too much about the private politics behind the public politics of the day. This knowledge is a burden to him in the eight stories, because he is able to uncover the injustices and corruptions of the murders in each story.