This book examines how pacemakers and defibrillators participate in transforming life and death in high-tech societies. In both popular and medical accounts, these internal devices are often portrayed as almost magical technologies. Once implanted in bodies, they do not require any 'user' agency. In this unique and timely book, Nelly Oudshoorn argues that any discourse or policy assuming a passive role for people living with these implants silences the fact that keeping cyborg bodies alive involves their active engagement. Pacemakers and defibrillators not only act as potentially life-saving technologies, but simultaneously transform the fragility of bodies by introducing new vulnerabilities. Oudshoorn offers a fascinating examination of what it takes to become a resilient cyborg, and in the process develops a valuable new sociology of creating 'resilient' cyborgs.