"The 39 Steps" is a thriller novel written by John Buchan in 1915. The story follows Richard Hannay, a man who becomes embroiled in a conspiracy after witnessing a murder. He is pursued by spies and must uncover a secret organization while trying to clear his name. The title refers to a mysterious organization involved in espionage. As Hannay travels across Scotland and England, he encounters various characters and dangerous situations. The novel is known for its fast-paced plot and has inspired numerous adaptations, including films and stage productions.