New technologies, and particularly the use of drones, have had transformative effects on the exercise of cross-boundary violence and warfare. Individuals specifically identified by the state are now often the central targets of military action. Other types of state-sponsored extraterritorial killing of individuals have also increased, or at least become more visible. The aim of this book is to spotlight the extraterritorial killings of opponents and to identify the building blocks of an emerging international legal framework to counter them.