Infrastructures are complex networks dominated by tight interdependencies between technologies and institutions. These networks supply services crucial to modern societies, services that can be provided only if several critical functions are fulfilled. This book proposes a theoretical framework with a set of concepts to analyse rigorously how these critical functions require coordination within the technological dimension as well as within the institutional dimension. It also shows how fundamental the alignment between these two dimensions is. It argues that this alignment operates along different layers characterized successively by the structure, governance and transactions that connect technologies and institutions. These issues of coordination and alignment, at the core of the book, are substantiated through in-depth case studies of networks from the energy, water and wastewater, and transportation sectors.