Espionage or spying is a practice of obtaining information about an organization or a society that is considered secret or confidential without the permission of the holder of the information. Unlike other forms of intelligence work, espionage 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. It also can be used as a general term to describe spying activities.
Espionage is usually part of an institutional effort (i.e., governmental or corporate espionage), and the term is most readily associated with state spying on potential or actual enemies, primarily for military purposes, but this has been extended to spying involving corporations, known specifically as industrial espionage. Many nations routinely spy on both their enemies and allies, although they maintain a policy of not making comment on this. In addition to utilizing agencies within a government many also employ private companies to collect information on their behalf such as SCG International Risk and others. Black's Law Dictionary (1990) defines espionage as: "...gathering, transmitting, or losing...information related to the national defense."
A spy is a person employed to obtain such secrets. The term intelligence officer is also used to describe a member of the armed forces, police, or civilian intelligence agency who specialises in the gathering, fusion, and analysis of information and intelligence in order to provide advice to their government or another organisation. In general, intelligence officers travel to foreign countries to recruit and "run" intelligence agents, who in turn spy on their own governments. These agents can be moles (who are recruited before they get access to secrets) or defectors (who are recruited after they get access to secrets).
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. 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 drug trafficking and those considered to be terrorists.