"Informed by research during the past half-century, the World Health Organization and other national health and health care bodies have increasingly emphasized the impact of social determinants of health on major health outcomes, including quality of life and longevity. One risk factor that has become increasingly prominent is loneliness-a subjective feeling of distress due to perceived social isolation. Loneliness has been shown to have major adverse mental and physical health effects throughout the life span. Loneliness: Science and Practice is, in part, a response to the National Academies of Science, Engineering and Medicine report released in early 2020 that called for screening for loneliness and social isolation in all health care practices and a need to develop best practices for addressing social isolation and loneliness in all medical subspecialty settings. As the COVID-19 pandemic and physical-distancing measures emerged in 2020, the need for the dissemination of knowledge of loneliness became even more pressing. This book reviews the important and growing literature on loneliness, focusing on evidence-based findings. It addresses both the science and the everyday practice of mental health care that involves the psychobiology of loneliness, its appropriate clinical assessment, and strategies to prevent and manage its adverse consequences"--