As part of the Double Cross operation, Jewish agent Renato Levi proved to be one of the Allies' most devastating weapons in World War II. ln 1941, with the help of Ml6, Levi built an extensive spy-ring in North Africa and the Middle East; most remarkably, it was entirely fictitious. Using recently declassified files, Nigel West details how Levi and his so-called CHEESE network helped the Allies thwart Rommel in North Africa, as well as diverting whole armies from the D-Day landing sites.