Espionage, Soviet History 61 Spies 56 Cold War 21 Foreign relations 20 Politics and government 16 Espionage 13 more ... Subversive activities 13 Communism 12 Officials and employees 12 Intelligence service 11 Communists 8 Intelligence officers 7 Cryptography 6 Espionage, American 6 Secret service 5 World War, 1939-1945 5 Authors, American 4 Journalists 4 Atomic bomb 3 Chemists 3 Defectors 3 Electrical engineers 3 Feminists 3 Political culture 3 Prisoners 3 Radicals 3 Relations 3 Right and left (Political science) 3 Social conditions 3 less ...