The Red House Mystery is a detective novel written by A.A. Milne. Unlike his famous Winnie-the-Pooh stories, this book is a classic murder mystery. The story revolves around the murder of a wealthy man at his country estate, the Red House, during a weekend gathering. Amateur detective Marlowe investigates the crime, using keen observation and logic to uncover the murderer. The novel is praised for its clever plot, suspenseful storytelling, and engaging characters, making it a memorable early 20th-century mystery.