Most wars have had some element of espionage and subterfuge, but few have included as much as the Second World War, where the all-embracing nature of the conflict, new technology, and the battle of ideologies conspired to make almost everywhere a war zone. The occupation of much of Europe in particular left huge areas that could be exploited. Partisans, spies and saboteurs risked everything in a limbo where the normal rules of war were usually suspended.
Concealment of oneself, one's weapons and equipment, was vital, and so were the new methods and hardware which were constantly evolving in a bid to stay ahead of the Gestapo and security services. Silent killing, disguise, covert communications and the arts of guerrilla warfare were all advanced as the war progressed.
With the embodiment and expansion of organisations such as the British SOE and the American OSS, and the supply of special forces units which operated behind enemy lines, clandestine warfare became a permanent part of the modern military and political scene. Perhaps surprisingly many of these hitherto secret techniques and pieces of equipment were put into print at the time and many examples are now becoming available.
