A review by slferg
The Mystery of the Yellow Room: Extraordinary Adventures of Joseph Rouletabille, Reporter, by Gaston Leroux

4.0

A locked room mystery which Agatha Christie considered one of the best.
Mathilde Stangerson is assulted and nearly killed in her room in the pavilion at her father's estate. The room is next to the laboratory where she had been working with her father on a chemistry experiment toward a theory they were working on. They had finished and she had gone to her room while her father and a servant were talking when they heard her screaming and they also heard a gunshot. They rushed to her room but the room was locked on the inside. Then the servant ran round to the window (which was barred). It also was locked and they could not get in. When they finally managed to break down the door, Mathilde was lying on the floor with scratches at her throat and a wound on her head, unconscious in the floor. There was also a bloody handprint on the wall.
Joseph Rouletabille, a young journalist, who has proved his ability for solving mysteries is interested in the case and talks his friend Sainclair to going down to the village where it happened and investigating with him. There is also a famous detective from the Surete there doing his own investigation, Frederic Larsan. Mathilde has not been killed, but is sorely wounded.
Larsan is convinced that it is her fiancee that has tried to kill her, but Rouletabille believes him innocent. But he has to pull all the clues together from divergent sources to find proof - especially since Mathilde will not tell them anything.