Network industries (energy, telecommunication, hardwaresoftware, etc.) have pulled the world’s growth during the two past decades. More generally, economic and social networks govern many aspects of humans’ life. This course analyses the peculiarities of economic behaviour, social interaction and strategic thinking in a network structure. The first part of the course is practical and focuses on the strategies of firms and governments on markets characterized by substantial network external effects. The second part, more theoretical, will introduce the basic concepts and tools to better understand economic, political and social interactions in a networked world.