Drawing on Actor-Network Theory (ANT) and its sibling notion of assemblage, this book offers a conceptual and methodological alternative to dominant social movement theory. The contributors explore empirical cases where science, technology, and activists intersect. They focus on the task of learning from the ways in which collectives assemble themselves around matters of concern, establish alliances with a number of human and non-human entities, and devise ways of caring for one another, or how they fail to meet these goals. They conclude that Actor-Network Theory is a useful tool in the construction of forms of attention and care that aspire to learn from social movements, rather than explaining them away.This book will be of interest to those studying activism and wider political and social movements, as well as those researching the interactions between science, technology, and society more generally. It was originally published as a special issue of Social Movement Studies.