This book examines the processes, practices and principles of defence planning in small and middle powers. Small and middle powers are recalibrating their force postures in this age of disruption. They are adapting their defence planning and military innovation processes to protect the security of their nations. This book examines defence planning and military innovation in eleven contemporary case studies of small and middle powers in North America, Europe, the Middle East, Asia and Oceania. Employing a structured focused comparison framework, it traces patterns in the choices of small and middle powers across the following themes: (1) alliances, dependencies and national ambitions; (2) approaches, processes, methods and techniques; and (3) military innovation strategies and outcomes. Breaking new theoretical ground, it offers a three-pronged typology distinguishing between the Strategic Defence Planner, the Transactional Defence Planners, and the Complacent Defence Planner. The book offers a rich array of insights into cases that fall across different geographies, strategic cultures, and governance systems. These insights can help guide discussions on how to structure decision-making structures, arrive at ambition levels, formulate priorities, select partners, and design defence planning and military innovation processes. This book will be of much interest to students of defence studies, security studies, public policy and International Relations, and will also be of interest to professionals in defence planning.