Espionage refers to the act of gathering information, generally using subversive means. A person who engages in espionage is called a spy. It is carried on by both governmental and private organizations. Intelligence bureaus operated by the military or the government, such as the CIA, KGB, MI5 and Mossad are among the more familiar known to the public. Subcontractors and front organizations also are frequently employed.
The word Espionage comes from the French word espionage, meaning literally "to spy". However, it was the Americans and Soviets who made the most historical use of espionage, during the Cold War. Almost all countries have used espionage, notably Israel, Germany during World War II, and Britain. Espionage is much less talked about today, except for industrial espionage, which is what happens when one company spies on another one, or a government spy agency tries to discover corporate secrets in another country.
Counterintelligence is the business of detecting and neutralizing spies.
- John Earl Haynes and Harvey Klehr. Venona: Decoding Soviet Espionage in America (2000) excerpt and text search
- K. Lee Lerner and Brenda Wilmoth Lerner. Encyclopedia of Espionage, Intelligence and Security (2003)
- Norman Polmar and Thomas B. Allen. Encyclopedia of Espionage (1997)
- Trahair, Richard C. S. Encyclopedia of Cold War Espionage, Spies, and Secret Operations (2004) online edition