Espionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, as the legitimate holder of the information may change plans or take other countermeasures once it is known that the information is in unauthorized hands. See clandestine HUMINT for the basic concepts of such information collection, and subordinate articles such as clandestine HUMINT operational techniques and clandestine HUMINT asset recruiting for discussions of the "tradecraft" used to collect this information.

History

Incidents of espionage are well documented throughout history. The ancient writings of Chinese and Indian military strategists such as Sun-Tzu and Chanakya contain information on deception and subversion. Chanakya's student Chandragupta Maurya, founder of the Maurya Empire, made use of assassinations, spies and secret agents, which are described in Chanakya's Arthasastra. The ancient Egyptians had a thoroughly developed system for the acquisition of intelligence, and the Hebrews used spies as well, as in the story of Rahab. Feudal Japan often used ninja to gather intelligence. More recently, spies played a significant part in Elizabethan England (see Francis Walsingham). Many modern espionage methods were well established even then.

The Cold War involved intense espionage activity between the United States of America and its allies and the Soviet Union and the People's Republic of China and their allies, particularly related to nuclear weapons secrets. Recently, espionage agencies have targeted the illegal drug trade and those considered to be terrorists.

Different intelligence services value certain intelligence collection techniques over others. The former Soviet Union, for example, preferred human sources over research in open sources, while the United States has tended to emphasize technological methods such as SIGINT and IMINT. Both Soviet political (KGB) and military intelligence (GRU ) officers were judged by the number of agents they recruited.

Various Forms

Unlike other forms of intelligence collection disciplines, espionage usually involves accessing the place where the desired information is stored, or accessing the people who know the information and will divulge it through some kind of subterfuge. There are exceptions to physical meetings, such as the Oslo Report, or the insistence of Robert Hanssen in never meeting the people to whom he was selling information.

The US defines espionage towards itself as "The act of obtaining, delivering, transmitting, communicating, or receiving information about the national defense with an intent, or reason to believe, that the information may be used to the injury of the United States or to the advantage of any foreign nation. Espionage is a violation of 18 United States Code 792-798 and Article 106, Uniform Code of Military Justice." The United States, like most nations, conducts espionage against other nations, under the control of the National Clandestine Service. Britain's espionage activities are controlled by the Secret Intelligence Service.