Leroux was an early 20 th century writer, detective and journalist. He is best known for writing The Phantom of the Opera. This mystery is one of the first \"locked room mysteries.\" A locked room mystery is one in which a crime is committed in what seems to be impossible circumstances. In this instance the criminal disappears from a locked room. | The Mystery of the Yellow Room by Leroux Gaston Leroux, Paperback | Indigo Chapters