No doubt, networks have become indispensable mathematical tools in many aspects of life in the twenty first century. They allow us to calculate all kinds of relational metrics and to quantify the properties of their nodes, clusters and global structures. These modes of calculation are becoming increasingly prevalent in an age of digital data. But networks are more than formal analytical tools. They are also powerful metaphors of our collective life, with all of its complexity and its many dependencies. This is why, among the various strategies of data visualization, networks seem to have assumed a paradigmatic position, spreading to the most different disciplines and colonizing sometimes as mere decoration a growing number of digital and non-digital objects. Contemplating the visual representation of a network, we don’t (always) need to compute its mathematical properties to appreciate its heuristic value – as anyone who has ever used a transportation plan knows well. Networks are extraordinary calculating devices, but they are also maps, instruments of navigation and representation. Not only do they guide our steps through the territories that they represent, but they also invite our imagination to see and explore the world in different ways. [First paragraph]