At the heart of renewed interest in the role of technology in global politics and the intensifying conversation between the discipline of International Relations (IR) and Science and Technology Studies (STS) is a distinct approach: Actor-Network Theory (hereafter: ANT). 1 ANT is an approach that has been developed in STS from the 1980s as an alternative to studying the making of scientific facts, objects and technologies. ANT is widely known for its unique take on technological objects and the idea to give them equal status to humans. Several overlapping concerns led to the development of the approach. Theoretically it was inspired by semiotics and literature theory, in particular the work of Gabriel Tarde and Michel Serres; but it was also an attempt to critique and advance post-structuralist ideas (Law 2009). In methodological terms ANT was influenced by ethno-methodology and its interest in everyday and practical activities. ANT is an established approach in STS, yet it is one which is continuously under construction and revision in the light of empirical problems. Although ANT is somewhat prominent and often seen as an emblem of STS achievements, one should not equate ANT and STS since, as the other chapters in this volume document, STS is a much richer and diverse field. ANT is best known for its claim to take materiality seriously. But, as our introduction shows, ANT is much more than this. It offers a rich repertoire of concepts and ideas, but also a profound rethinking of how we do scientific analysis.