History Secret service World War, 1939-1945 36 Spies 26 Intelligence service 20 Military intelligence 15 Espionage 12 more ... Campaigns 7 Cold War 7 Espionage, German 7 Internal security 7 Underground movements 7 Police 6 Politics and government 6 Espionage, British 5 Intelligence officers 5 Foreign relations 4 Military campaigns 4 Aerial operations, American 3 Aerial operations, British 3 Air pilots, Military 3 Anti-Nazi movement 3 Escapes 3 Espionage, American 3 Flight crews 3 Histoire 3 Naval operations 3 Officers 3 Officials and employees 3 Submarine 3 less ...