Organisations have always operated, constructed and generated networks and, contrary to the notion that it is a new phenomenon, study of such networks or groups has long existed. Their analysis has forever been the central task of counter-espionage services and for more than a century that of the intelligence staffs of military headquarters. Analysis of communication networks (communications order of battle, or ORBAT), which originally appeared in the Second World War, continues today in the form of electronic warfare in certain areas of operation.

As they are generally understood, these networks are by nature groups of human beings who make use of the range of technical assets available to them for communication. Nevertheless, given that the technical assets themselves have a considerable influence on the information and communication concerned, we tend to talk today of a socio-technical mechanism to describe a collection of individuals communicating through an information and communication system. Analysis of any network must therefore look at both its human and its technical aspects, and is made up of numerous different levels and analysis grids necessary for its understanding. These would include the group of individuals who are communicating, the social structure of the network, the technical means available to them and the flows of information and their content, all related to the intentions, the role and the nature of the network.

This preliminary knowledge of a network leads to an understanding of its study for operational purposes without falling into the trap of over-simplification. It hardly needs saying that a network is a complex system: it can be open, like a marketplace, or closed, like a private space, or even both, as would be the case with invisible groups within an open network. It represents a number of interactions which rely on the principle of exchange and sharing—for example, of identity and fraternity (old boys’ networks and rites societies), of knowledge (professional groups and think tanks), of information (intelligence networks) or of action (terrorist networks). This idea of a community is inseparable from that of the individual culture of each network, which is in turn a function of identity, history, methodology, language and of values to be shared, defended or debated.