The Thirty-nine Steps is a novel by Scottish author John Buchan. The narrative of the novel is simple to follow and is similar to other novels in the spy-thriller genre. The story begins by describing the protagonist's South African background. He has lived there for many years and has accumulated wealth as a mining engineer. We then see Richard Hannay's dissatisfaction with England, particularly English culture and people. He finds it rather dull and desires to move back to South Africa.

Although this seems like a simple background detail, or merely a way to setup the climax in the story, his dissatisfaction with English life frames the overarching theme of the novel: English nationalism. Like many other fictional works from Great Britain in the spy or war genres, The Thirty-nine Steps has a nationalistic theme. Within this larger theme is the sub-theme of defending English soil and sovereignty.

The root of this theme's recurrence in the genre is the actual experiences of English people during World War I and World War II. There is a hint of mass trauma among the British people, and this is evident in the countless period films, television series, and fictional work containing such themes. The Thirty-nine Steps was published during Great Britain's involvement in World War I and at a time when paranoia over espionage plagued the country.

Another theme, which is not as evident, is the UK's tense relationships with the rest of Europe. The British Isles has had a tumultuous relationship with continental Europe since the beginning of ancient British civilization, and it continues to this day (e.g., Brexit).