Despite its long existence and international acceptance, network theory and analysis is a practically unknown approach in Documentation, both theoretically and methodologically speaking. Fortunately, this trend is changing, inasmuch as network theory and analysis may mean a quantitative and qualitative leap forward in the representation and analysis of the structure of all types of scientific domains, whether geographic, thematic or institutional. The extraordinary advances that have taken place in recent years in the study and analysis of complex networks have been made possible by a number of parallel developments. First of all, with computerized data acquisition and handling, large databases can bemanaged, leading to the emergence of different real network topologies. Secondly, the increase in computing power has made it possible to explore networks with millions of nodes. Thirdly, there is the slow but sure breakdown of boundaries between disciplines. This can be seen by researchers because of their ability to access and use databases that facilitate an understanding of the generic properties of complex networks.