Total defence, as a concept, combines and extends military and civil defence: in a state of war or emergency, all social institutions mobilize to defend the state. Total defence forces, led by a diverse workforce of defence and security professionals, are critical to both national defence and international security goals.Total Defence Forces in the Twenty-First Century looks at the various groups that make up this workforce: members of the military’s regular force, reservists, defence civil servants, and contractors working for private military and security companies. When civilian staff and military personnel work towards a common goal, their distinct professional cultures and identities can make integration challenging. Despite the often high levels of partnership, underlying differences affect the quality of the collaboration and, ultimately, organizational and operational effectiveness. Defence ministries around the world are increasingly recognizing the importance of optimizing the ways in which they employ and integrate civilian and military personnel.This volume focuses on a critical question: what are the main challenges to workforce integration and collaboration, and how can such challenges be overcome to deliver the full potential of the total defence force? Together, scholars and practitioners provide some answers.