This book addresses the origins, determinants and magnitude of the global problem of sedentary behaviour, along with concise yet in-depth solutions for tackling it. As a consequence of major technological advances in modern society, many people find themselves in environments characterized by prolonged sedentary behaviour. Building on the contributions of leading experts in the field, the new edition of this book presents updated knowledge about sedentary behaviour, its medical and public health significance, its correlates and determinants, measurement techniques, and recommendations for addressing this behaviour at the individual, community, environmental, and policy level. The book encompasses current research linking the COVID-19 pandemic to increased levels of sedentary behavior, and it covers global and planetary health aspects of sedentary behavior, highlighting sustainable development goals such as health and well-being for all. Applying a cross-disciplinary methodology, the book avoids considering physical activity and sedentary behavior as a single continuum, which potentially hampers progress in confronting widespread levels of sedentariness. Rather, the book helps readers better understand how sedentary and physically active behavior co-occur and how the two behaviours have distinct contributing factors. Building on the contributions of distinguished international experts in the field, this thorough resource is a valuable asset and challenges professionals, researchers, students, and practitioners alike to adopt new strategies and expand their reach.