The Cheyne Mystery is a 1926 mystery thriller novel by Freeman Wills Crofts. It is the second in his series of novels featuring Inspector French, a prominent figure of the Golden Age of Detective Fiction. It followed on from his debut in Inspector French's Greatest Case, in which Crofts introduced a character who was more methodical and less flamboyant than many of the other great detectives who followed in the wake of Sherlock Holmes.