Gaston Louis Alfred Leroux (6 May 1868 – 15 April 1927) was a French journalist and author of detective fiction.
In the English-speaking world, he is best known for writing the novel The Phantom of the Opera (Le Fantome de l'Opera, 1910), which has been made into several film and stage productions of the same name, notably the 1925 film starring Lon Chaney, and Andrew Lloyd Webber's 1986 musical. His novel The Mystery of the Yellow Room is also one of the most famous locked-room mysteries ever.
Leroux was born in Paris in 1868 and died in 1927 in Nice. He went to school in Normandy and studied law in Paris, graduating in 1889. He inherited millions of francs and lived wildly until he nearly reached bankruptcy. In 1890, he began working as a court reporter and theater critic for L'Echo de Paris. His most important journalism came when he began working as an international correspondent for the Paris newspaper Le Matin. He was present at, and covered, the 1905 Russian Revolution.
Another case at which he was present involved the investigation and in-depth coverage of the former Paris Opera (presently housing the Paris Ballet). The basement contained a cell that held prisoners of the Paris Commune.
He suddenly left journalism in 1907 and began writing fiction. In 1919, he and Arthur Bernede formed their own film company, Societe des Cineromans, to publish novels and simultaneously turn them into films. He first wrote a mystery novel titled Le mystere de la chambre jaune (1908; The Mystery of the Yellow Room), starring the amateur detective Joseph Rouletabille. Leroux's contribution to French detective fiction is considered a parallel to Sir Arthur Conan Doyle's in the United Kingdom and Edgar Allan Poe's in the United States.
Leroux published his most famous work, The Phantom of the Opera, as a serial in 1909 and 1910, and as a book in 1910 (with an English translation appearing in 1911).
Leroux was made a Chevalier de la Legion d'honneur in 1909.