Espionage is the secret gathering of information on rival countries for military purposes. Espionage can be used in business, military, economic or political decisions however; it is commonly employed government for defensive tactics. Espionage or spying is illegal in many nations however, it gains profits from agencies to protect the secrecy of information that is desired.
Espionage is an old ancient craft; it has been used through out history. The Bible's book of Joshua (The Old Testament) states that the leaders secretly sent out spies to reconnoiter a country. Also the Chinese Military theorist Sun Tzu's, who wrote a book The Art Of War written in 500 B.C, provides instruction for organizing an espionage system with agents and defectors also known as rebels. Homer a Greek philosopher who wrote "Illiad" mentions the Egyptians had a well-developed secret service and spying agents. During the middle ages Joan of Arc , the world renown female spy was betrayed by Bishop Pierre Cauchon of Beavais, As a result Sir Francis Walsingham developed an efficient political spy system for Elizabeth I. During the American Revolution, Nathan Hale and Benedict Arnold achieved their fame as spies during the U.S. Civil War.
In the United States the CIA or the Central Intelligence Agency is the main agency for gathering secret information and responsible for operations outside the United States. The FBI or Federal Bureau of Investigation has the primary responsibility for counterespionage activities within the United States. Counterespionage is when a country or an organization captures a hostile spy and turns them into a so-called "double agent" who sends false information to their own organization. It prevents other nations from gaining such information. Under international law, these activities are not illegal, but individual nations have laws against spying. However, spies are not considered with common or uncommon