This open access book provides a comparative analysis of the deployment of the military in domestic operations, the use of the armed forces during the COVID-19 pandemic, and the impact of that deployment on civil-military relations in 26 countries worldwide. The book examines the legal and constitutional regulations under which the military can serve in domestic roles, and the extent of domestic deployment before the COVID-19 pandemic. It focuses on the roles in which the military served during the pandemic, the resources available, and the readiness and effectiveness of the military response. The volume addresses whether or not the pandemic response was securitized, the extent of civilian oversight and control, the accountability measures in place, and the impact of the COVID-19 deployment on the military’s image. The volume captures the lessons learnt from the COVID-19 deployment and the implications for future force design, structure, and organizational transformation. Since almost all countries used their military in some capacity to respond to the COVID-19 pandemic, this volume offers an opportunity to compare use of the armed forces to provide domestic humanitarian assistance and disaster response.