The concept of "infrastructure" typically refers to large-scale "physical" and material systems necessary for human organization and activity, such as roads and bridges, grids and sewers. A significant amount of work in geography, anthropology and science and technology studies (STS) has been devoted to exploring the power dynamics, conflicts and disputes, meanings and social relationships embodied in these "physical" infrastructures (for example, Harvey, 2012;Larkin, 2013). However, in the field of ICTs, especially since the introduction of the Internet as a "general-public" technology, an exclusively physical definition of infrastructure might not be the most appropriate. As Geoffrey Bowker and his colleagues point out, "beyond bricks, pipes or cables, infrastructure also includes more abstract entities, such as protocols, standards and memory [… and facilities such as] computing services, help desks and data directories" (Bowker et al., 2010, p. 97). This chapter will take stock of work conducted in the last decade to address how the concept of infrastructure -more particularly information and digital infrastructure, in its different "materialities" -can be mobilized as a heuristic instrument to understand the governance of information and digital technology, especially the Internet. The chapter will discuss the extent to which the infrastructural quality of the "network of networks", rather than natural or inherent, is relational and conditional; and it will examine how, for a better understanding of