The Crooked Hinge
John Dickson Carr
 In his ninth outing, Dr. Fell spends July 1937 at a small village in Kent. John Farnleigh is a wealthy young man married to his childhood love, and a survivor of the Titanic disaster. When another man comes along claiming to be the real John Farnleigh, an inquest is scheduled to determine which individual is the real Farnleigh. Then the first Farnleigh is killed—his throat is slashed in full view of three people, all of whom claim that they saw no one there. Later, a mysterious automaton reaches out to touch a housemaid, who nearly dies of fright, and a thumbograph (an early toy associated with the taking of fingerprints) disappears from a locked library. Dr. Gideon Fell investigates and reveals the surprising solution to all these questions.