The Mystery of the Yellow Room by Gaston Leroux is a pioneering classic of detective fiction, first published in 1907. The novel centers on a daring attack on Mathilde Stangerson, daughter of a renowned scientist, inside a locked room that appears impossible to enter or exit. Investigative journalist Joseph Rouletabille takes on the case, unraveling clues with logic and intuition. As suspicion falls on jealous lovers, rivals, and hidden enemies, the mystery deepens with twists, red herrings, and psychological tension. Celebrated as one of the first "locked-room" mysteries, the novel blends suspense, forensic detail, and courtroom drama. A masterpiece of early crime fiction that influenced generations of mystery writers.