ABSTRACT
This entry introduces some of the main concepts and methods of the science studying complex, self-organizing systems, and networks, in a nontechnical manner. Complexity cannot be strictly defined, it is only situated between order and disorder. A complex system is typically modeled as a collection of interacting agents, representing components as diverse as people, cells, or molecules. Because of the nonlinearity of the interactions, the overall system evolution is to an important degree unpredictable and uncontrollable. However, the system tends to self-organize, in the sense that local interactions eventually produce global coordination and synergy. The resulting structure can, in many cases, be modeled as a network, with stabilized interactions functioning as links connecting the agents. Such complex, self-organized networks typically exhibit the properties of clustering, being scale-free, and forming a small world. These ideas have obvious applications in information science when studying networks of authors and their publications.
