MICHAEL GILBERT. The Danger Within (1952).

Take the prison-break plot and the barbed-wire scenery of classic POW-camp movies such as Stalag 17 (1953) and The Great Escape (1963), add a clever murder puzzle, stir in a dash of dry English wit, and the happy result is this hybrid mystery-adventure novel. In fact, those two films appeared after this curiously little-known masterpiece, so the line of influence (if any) likely runs in the other direction. Set during the summer of 1943 in an Italian camp for captured British officers, the story marches forward on three interconnected levels. Most broadly, there is the world-historic drama of the Allied invasion of Italy, an event whose distant thunder echoes in the background to the brief, tension-wrought scenes that unfold here. One level down, there is the saga of 400 scheming Brits and the boarding-school exploits that make up their campaign to burrow out of the camp before the Carabinieri, the Nazis, and the spies within their own ranks can stop that effort. Finally, there is a tale of death and detection. The slain body of a Greek prisoner, who might have been one of those spies, turns up beneath a pile of sand in an escape tunnel, and the Fascist swine who runs Campo 127 charges another inmate with the crime. Did a member of the British escape team commit murder in order to prevent discovery of the tunnel? It falls to another prisoner, a scholarly sort named “Cuckoo” Goyles, to investigate the matter. The exposition of his sleuthing gets muddled somewhat, as larger forces sweep through the camp—and hence through the book. Still, even amid chaotic wartime conditions, the spirit and the habits of English justice prevail.