The characters in The Thirty-Nine Steps are Richard Hannay, Franklin P. Scudder, Constantine Karolides, Sir Harry, Sir Walter Bullivant, and the Black Stone.
Richard Hannay is the main character, or the protagonist, and the narrator of the story, which is written in first person. He has been living outside of his native country of Scotland. He has just returned to his country from South Africa where he was working as a mining engineer. He is given the secret knowledge of Scudder, in code, about the plans of the Black Stone. He flees to Scotland to hide and to give the information he has to the authorities and to avoid sharing Scudder's fate.
Franklin P. Scudder is an American investigator. He knows about the Black Stone's plans and is afraid of being murdered because of it. He gives the information to Hannay in code before he is murdered.
Constantine Karolides is a politician from Greece who is also murdered by the Black Stone.
Sir Harry is a blooming politician and a landowner in Scotland who becomes friends with Hannay.
Sir Walter Bullivant is a relative of Sir Harry who works at the Foreign Office. He does not believe the information Hannay relays at first, but when Karolides is murdered, he becomes convinced and passes the information on to government authorities.
The Black Stone is a group of people rather than one specific person. This is a group of spies who are helping to prepare for a German invasion of England. They are apprehended while trying to escape England.
Richard Hannay, a well-to-do retired mining engineer. Wishing to protect himself from Scudder’s murderers and to relay to proper authorities Scudder’s secret coded information (in a small black book), Hannay escapes to Scotland to hide but at the same time gives the impression that he killed Scudder. He evades the pursuing Black Stone and the police, as well as decoding Scudder’s book; by doing so, he learns of invasion plans against England and informs Sir Walter....
(The entire section is 506 words.)