Gaston Leroux 
The Mystery of the Yellow Room 

The Mystery of the Yellow Room is a classic detective novel by Gaston Leroux. It tells the story of a young reporter named Joseph Rouletabille who is tasked with solving a mysterious and seemingly unsolvable crime. The crime takes place in the titular Yellow Room, a locked room where a young woman is attacked and seemingly disappears without a trace. Rouletabille must use his wit and intuition to uncover the truth behind the mystery, while navigating a web of deceit and dangerous characters. The book is considered one of the earliest examples of the locked room genre and is known for its intricate plot and engaging characters.