Leroux was a successful journalist before turning to fiction, where he became a master of the 'locked-room' mystery and detective stories. His creation, the detective Rouletabille, appeared in several novels including The Mystery of the Yellow Room. However, it is the Gothic masterpiece The Phantom of the Opera that brought him enduring global fame. His writing combined suspense, romance, and macabre atmosphere, influencing both detective fiction and horror cinema throughout the 20th century.