Published just before the turn of the millennium, Between Silk and Cyanide is the wartime memoir of Special Operations Executive agent Leo Marks. It details the three and a half years he spent collaborating with field agents in Nazi-occupied countries across Europe, deciphering their messages and doing his best to ensure their safety. This memoir is every bit as surreal, dark and emotionally turbulent as any fictional war novel, rising to the heights of novels such as The Naked and the Dead and Catch 22. The light, almost flippant tone Marks narrates with only serves to add to the incredulity of this true tale.

This is a book that manages to show the relationship between the intellectual — the cold mathematical world of cryptography — and the human elements of war; Marks’ stories and anecdotes about various spies he trained and worked with lend a much needed brevity to the dark world of the early 1940s. It’s this human element, especially the little moments of interaction between people, that brings home again and again the jaw-dropping realisation to a reader that these people and these conditions actually existed. This is a nonfiction story at once more incredible, unbelievable and emotional than most fiction.