When a valuable diamond is stolen from a safe, all evidence points to a single, incriminating fingerprint. But Dr. John Thorndyke, a brilliant forensic investigator, suspects that the case is not as straightforward as it seems. Using logic, scientific analysis, and a deep understanding of criminal deception, he sets out to unravel a mystery where appearances are dangerously misleading. A pioneering work in forensic detective fiction, The Red Thumb Mark introduces readers to the meticulous and ingenious methods of one of literature's greatest sleuths.