"The Big Four," published in 1927, represents an intriguing departure from Christie's usual style, blending elements of the detective novel with the emerging thriller genre. Originally published as a series of short stories in The Sketch magazine, the novel was later compiled and adapted into a single narrative. This unique genesis is reflected in its episodic structure and its more sensational, conspiracy-driven plot.

The story follows Hercule Poirot as he confronts a global conspiracy led by four criminal masterminds known as "The Big Four." This narrative choice reflects the growing anxiety about international tensions and secret societies in the interwar period. The novel's themes of global power struggles and the fear of hidden influencers resonate with the political climate of the late 1920s, foreshadowing the international conflicts that would emerge in the following decade.

From a literary perspective, "The Big Four" showcases Christie's experimentation with genre boundaries. While it retains elements of the traditional detective story, it incorporates more action-oriented sequences and a broader, more geopolitical scope than her previous works. This blend of styles anticipates later developments in the thriller genre and demonstrates Christie's awareness of changing reader tastes.

Scholars have noted that the novel's portrayal of non-Western characters, while problematic by modern standards, provides insight into the prevailing attitudes and stereotypes of the period. The book's reception and its place in Christie's canon offer valuable material for studying the evolution of both her writing and the broader trends in popular fiction during the interwar years.