Monitoring is the act of observing activities (human in general) or a place. Technically, we also speak of supervision or monitoring.

Secret or obvious, it is old; 2,500 years ago, Sun Tzu’s The Art of War, described how to use spies against enemies. Recently, modern electronics and computer technology, together with the development of satellites, the internet and the smartphone, have opened up new fields and means of surveillance (individual or mass).

Counter-surveillance is the set of measures and techniques aimed at preventing surveillance. Counter-surveillance includes electronic methods such as the detection of surveillance devices (eavesdropping devices and cameras). Most often, counter-surveillance includes a set of actions (countermeasures) that reduce surveillance risks.