Quick Answer: Espionage, spying, or intelligence gathering, as a subfield of the intelligence field, is the act of obtaining secret, confidential, or in some way valuable information. Such information is also referred to as intelligence. A professional trained in conducting intelligence operations by their government may be employed as an intelligence officer. Espionage may be conducted in a foreign country, domestically or remotely. The practice is clandestine, as it is by definition unwelcome. In some circumstances, it may be a legal tool of law enforcement and in others, it may be illegal and punishable by law. Espionage is often part of an institutional effort by a government or commercial concern. The term is frequently associated with state spying on potential or actual enemies for military purposes. However, there are many types of espionage. Industrial espionage, for example, involves spying on civilians and their respective business or corporate interests.