This book explores the emergence of a new scientific field, synthetic biology, and the many bold promises its proponents have made to change the future of science, industry, humanity and the global environment. It explores how people, including academics, students, industrialists and governance actors, tried to change their practices to bring engineering and biology together, and to realise such promises from within their everyday lives. It focuses on an ethnographic case study of an academic project that aimed to demonstrate the field's promise for solving water industry problems, from leaky pipes to climate change. In doing so, the book weaves together stories of barriers, bacteria and bodies, examining how they were entangled as people tried to make connections between academia and industry. It also reflects on the authors' attempts to work collaboratively with natural scientists and engineers, reflecting on current debates about the role of sociology in such interdisciplinary projects. The book contributes to contemporary studies of science and technology by highlighting issues such as ontology, practices, failure and time.