- Fair for Its Day / Values Dissonance: Buchan's writing can tend towards the jingoistic when read with modern eyes, but it's nowhere near as bad as some other authors writing at the time; in fact, when compared to works such as Bulldog Drummond, Hannay and Buchan are downright progressive. Greenmantle in particular shows detailed knowledge of and respect for Islam.
- Foe Yay: Stumm in Greenmantle. Examples of it include Stumm's man-on-man fight in his rather frilly drawing room and intruding upon Hannay while he's getting dressed. (It's even worse when you read it.)
- Magnificent Bastard: Most of the villains.
- Nightmare Fuel: Mary's description of what she's going to do to the bad guy in The Three Hostages makes the good guys quake in their shoes.