Among his "American" works are L'Agent triple (1962), Métro pour l'enfer (1963), Les Mousquetaires de la République (1964) and Vers une métrique française (1977).
Throughout the 1970s under his pseudonym Lieutenant X, Volkoff published stories for teenagers in the Langelot series of Hachette's Bibliothèque verte imprint, featuring the adventures of the eponymous hero, a young French secret agent.
In the later 1970s, with the standoff between East and West a constant reality, Volkoff's writings analyzed the ideological combat between two opposing conceptions of the world and of freedom with a solid geopolitical background.
Dedicated to Graham Greene, whom Volkoff greatly admired, the novel's title refers to the intelligence manoeuvre of turning an uncovered enemy agent to one's own side.
In 1985, inspired by his American experience, he published Le professeur d'histoire (The History Teacher), in which he portrayed a comic confrontation between a literary man filled with tradition and a young heiress surfing the wave of modernism.
Power, manipulation, battles of influence and disinformation take a central role in many of his books, such as L'Interrogatoire (1988) and Les Hommes du Tsar (1989), a historical novel about Russia from the death of Ivan the Terrible to the advent of the Romanovs.