This book proposes alternative ways to engage with computer security, rooted in Science and Technology Studies (STS) and extensive ethnographic observations. Computer security, the author argues, is part of living in the Anthropocene - an age of damaged more-than-human relations. As such, doing computer security means not striving for technical solutions, or individual awareness, but living with fragility. The book suggests conceptual approaches and methods of studying computer security which contribute to current debates on infrastructural breakdown and ecological ruins in STS and Anthropology, while offering new perspectives to Usable Security and Critical Security Studies.