The Mystery of the Yellow Room" is a detective novel written by Gaston Leroux and first published in 1907. The novel is set in France and follows the story of a young woman named Mathilde Stangerson, who is attacked in her bedroom. Despite being locked from the inside and having no visible means of entry or exit, her attacker manages to escape, leaving her father and the police baffled.
The novel's protagonist is a young journalist named Joseph Rouletabille, who is determined to solve the mystery and uncover the identity of the attacker. Rouletabille uses his keen powers of observation and deduction to sift through the evidence and interview the suspects, ultimately unraveling a complex web of secrets and deceit.

"The Mystery of the Yellow Room" is known for its intricate plot and clever use of misdirection, and has been compared to other classic detective novels, such as those by Sir Arthur Conan Doyle. The novel is considered a landmark in the development of the detective genre and has been influential in the decades since its publication.