I have long considered The Thirty-Nine Steps, Buchan’s first (and shortest) Hannay novel, to be good clean fun. It is a thrilling spy tale that is elegantly implausible and crisply confident, standing up well to multiple re-readings. Of the following three novels, I thought The Three Hostages to be closest in style and would give both it and the first story a solid 5/5.
The two middle novels fall off somewhat – both are sprawling stories, full of dry details and unnecessary tangents, while the second suffers from its ham-fisted treatment of the romantic subplot (for which failings I would rate them 3/5). Still, it was fun to become better acquainted with self-deprecating, ex-mining engineer Richard Hannay, part-time spy and full-time war hero.
[Why I read it: it got on my radar when I saw my brother reading it, especially since I was already a fan of the first novel.]