An intelligence agency is a government agency responsible for the collection, analysis or exploitation of information and intelligence in support of law enforcement, national security, defence and foreign policy objectives. Means of information gathering are both overt and covert and may include espionage, communication interception, cryptanalysis, cooperation with other institutions, and evaluation of public sources. The assembly and propagation of this information is known as intelligence analysis or intelligence assessment.
Intelligence agencies can provide the following services for their national governments.
- Provision of analysis in areas relevant to national security;
- give early warning of impending crises;
- serve national and international crisis management by helping to discern the intentions of current or potential opponents;
- inform national defence planning and military operations;
- protect sensitive information secrets, both of their own sources and activities, and those of other state agencies;
- may act covertly to influence the outcome of events in favour of national interests, or influence international security; and
- Defence against the efforts of other national intelligence agencies (counter-intelligence).
There is a distinction between "security intelligence" and "foreign intelligence". Security intelligence pertains to domestic threats (e.g. terrorism, espionage). Foreign intelligence involves information collection relating to the political, or economic activities of foreign states.
Some agencies have been involved in assassination, arms trafficking, coups d'état, and the placement of misinformation (propaganda) as well as other covert operations, in order to support their own or their governments' interests.
See also 
- List of intelligence agencies
- List of defunct intelligence agencies
- List of intelligence gathering disciplines
Further reading 
- Encyclopedia of espionage, intelligence, and security, hrg. von K. Lee Lerner und Brenda Wilmoth Lerner, 3 Bände, Detroit [u.a.] : Gale [u.a.], 2004
- Rhodri Jeffreys-Jones, Cloak and Dollar: A History of American Secret Intelligence, Yale University Press, 2002
- Richard C. S. Trahair, Encyclopedia of Cold War espionage, spies, and secret operations, Westport, Conn. [u.a.] : Greenwood Press, 2004
- Amy B. Zegart, Flawed by design : the evolution of the CIA, JCS, and NSC, Stanford, Calif. : Stanford Univ. Press, 1999
- Цибулькін В. В., Рожен Л. М., Вєдєнєєв Д. В. та ін. Нариси з історії розвідки суб'єктів державотворення на теренах України / Заг. ред. П. Д. Морозов. — К.: «Преса України», 2011. — 536 с., іл.
- The Journal of Intelligence History
- Ruiz, Victor H., 2010. "A Knowledge Taxonomy for Army Intelligence Training: An Assessment of the Military Intelligence Basic Officer Leaders Course Using Lundvall’s Knowledge Taxonomy". Applied Research Projects. Texas State University Paper 331. http://ecommons.txstate.edu/arp/331
- world intelligence rankings
- Intelligence News
- Outsourcing Intelligence
- Article on intelligence services by the Geneva Centre for the Democratic Control of Armed Forces
- Proposal for a Privacy Protection Guideline on Secret Personal Data Gathering and Transborder Flows of Such Data in the Fight against Terrorism and Serious Crime by Marcel Stuessi
- Intelligence Online Investigative news and reporting on intelligence agencies world-wide.
- All mentions of international intelligence agencies filtered from the online news stream by Social Elephant