“intelligence” are personal smarts and espionage. This survey
deals mainly with the latter.
Intelligence agencies that operate in secret are politically problematic. Those that operate openly, such as the U.S. Census Bureau, usually are not. Intelligence agencies that seek secrecy often argue that this is necessary either because what they want to find out isn’t public, or because their sources would surely protest, dissemble or dry up if they knew they were being monitored. The problem is that no matter how well-justified, secrecy also makes oversight, external direction, and control difficult. Moreover, a covert network for information-gathering
provides an all too handy infrastructure for carrying out secret interventions: events can not only be reported, they can be caused.
