In the last few years, a spirit has been haunting our academic and popular culture — the spirit of networks. Throughout social as well as natural sciences, more and more phenomena have come to be conceived as networks. Telecommunication networks, neural networks, social networks, epigenetic networks, ecological and economic networks , the very fabric of our existence seems to be made of lines and dots. More recently, the interest for graphs overflowed from science to popular culture and images of networks started to appear everywhere. They decorate buildings and objects; they are printed on t-shirts and furniture; they colonize the desktop of our computers and the walls of our airports. Networks have become the emblem of modernity, a way to show and tell our world’s complexity. Our growing fascination for networks is not unjustified. Networks are powerful conceptual tools, encapsulating in a single object multiple affordances for computation (networks as graphs), visualization (networks as maps) and manipulation of data (networks as interfaces).