This book sets out with a programmatic agenda to find new ways of “speaking for the social” in projects of technical and infrastructural change. It takes as its starting point the ongoing challenge of com-munication between scholars in the social sciences and humanities who study the social dimensions of technical and infrastructure projects, and those working in engineering and policy who seek bring about social change through technical interventions. Rather than locating this difficulty in the bifurcation of epistemic cultures along a fault line of technical versus social disciplines, what we propose in this volume is that this communicative challenge rests on deep, but often unarticulated distinctions in the way “the social” is itself conceptualized, developed, enacted, and deployed within the social sciences, humanities, engineering, and policy. Taking this as our starting point, the chapters of this book present a series of creative, experimental, collaborative, and revisionist approaches to tracing, unravelling, and communicat-ing the social dimensions of technical projects, each of which emerges from the confrontation of different implicit understandings of what the social is, where one might find it and how it can be accounted for. What results is a catalogue of concrete and yet contingent methods for engaging the social dimen-sions of technical projects that neither simplifies the social as the site of measurable impact, nor relativizes the social as so endlessly complex that it cannot be pinned down.