Violence is a global public health issue. This article is an introduction to the World Report on Violence and Health, published by the World Health Organization (WHO). It describes the phenomenon and raises basic questions: concepts and definitions of violence; the current state of knowledge; the nature and types of violence; a quantitative and qualitative approach using an ecological model; the role and potential of the public health sector in preventing and reducing violence; the responsibilities of nations and policymakers in an intersectoral context; and the challenges and obstacles for implementation. Violence has always been part of human experience, but its impact is visible in many forms worldwide. Each year, over a million people die from self-inflicted, interpersonal, or collective violence, and many more suffer non-fatal injuries. Violence is among the leading causes of death for people aged 15-44 globally. The cost of violence is measured in billions of dollars in health care expenditures and lost productivity. The human cost in grief and pain is difficult to quantify, as much of it is invisible. While satellite technology makes certain types of violence visible, much more occurs out of sight in homes, workplaces, and institutions. Some causes of violence are easy to see, while others are deeply rooted in social, cultural, and economic factors. Recent research suggests that while biological factors explain some predisposition to aggression, they often interact with family, community, cultural, and other external factors to create situations where violence is likely to occur. Despite the presence of violence, systems have been developed to prevent or limit it. Public health has become a growing asset in this response, with practitioners, researchers, and systems working to understand the roots of violence and prevent its occurrence. Violence can be prevented and its impact reduced, similar to how public health efforts have prevented and reduced pregnancy-related complications, workplace injuries, infectious diseases, and illnesses from contaminated food and water. The factors contributing to violent responses can be changed. Public health is characterized by its emphasis on prevention, not just accepting or reacting to violence. It is interdisciplinary and science-based, drawing on knowledge from many disciplines, including medicine, epidemiology, sociology, psychology, criminology, education, and economics. It emphasizes collective action, as cooperative efforts from various sectors are necessary to solve problems that are often seen as purely medical. The public health approach to violence is based on the scientific method, with four key steps: 1) gathering as much basic knowledge as possible about all aspects of violence; 2) investigating why violence occurs; 3) exploring ways to prevent violence; 4) implementing interventions. Public health is above all characterized by its emphasis on prevention, starting with the strong conviction that violent behavior and its consequences can be prevented. Violence is defined as the intentional use of physical force or power, threatened or actual, against oneself, another person, or a group or community that results in or is likely to result in injury, death, psychological harm, maldevelopment,Violence is a global public health issue. This article is an introduction to the World Report on Violence and Health, published by the World Health Organization (WHO). It describes the phenomenon and raises basic questions: concepts and definitions of violence; the current state of knowledge; the nature and types of violence; a quantitative and qualitative approach using an ecological model; the role and potential of the public health sector in preventing and reducing violence; the responsibilities of nations and policymakers in an intersectoral context; and the challenges and obstacles for implementation. Violence has always been part of human experience, but its impact is visible in many forms worldwide. Each year, over a million people die from self-inflicted, interpersonal, or collective violence, and many more suffer non-fatal injuries. Violence is among the leading causes of death for people aged 15-44 globally. The cost of violence is measured in billions of dollars in health care expenditures and lost productivity. The human cost in grief and pain is difficult to quantify, as much of it is invisible. While satellite technology makes certain types of violence visible, much more occurs out of sight in homes, workplaces, and institutions. Some causes of violence are easy to see, while others are deeply rooted in social, cultural, and economic factors. Recent research suggests that while biological factors explain some predisposition to aggression, they often interact with family, community, cultural, and other external factors to create situations where violence is likely to occur. Despite the presence of violence, systems have been developed to prevent or limit it. Public health has become a growing asset in this response, with practitioners, researchers, and systems working to understand the roots of violence and prevent its occurrence. Violence can be prevented and its impact reduced, similar to how public health efforts have prevented and reduced pregnancy-related complications, workplace injuries, infectious diseases, and illnesses from contaminated food and water. The factors contributing to violent responses can be changed. Public health is characterized by its emphasis on prevention, not just accepting or reacting to violence. It is interdisciplinary and science-based, drawing on knowledge from many disciplines, including medicine, epidemiology, sociology, psychology, criminology, education, and economics. It emphasizes collective action, as cooperative efforts from various sectors are necessary to solve problems that are often seen as purely medical. The public health approach to violence is based on the scientific method, with four key steps: 1) gathering as much basic knowledge as possible about all aspects of violence; 2) investigating why violence occurs; 3) exploring ways to prevent violence; 4) implementing interventions. Public health is above all characterized by its emphasis on prevention, starting with the strong conviction that violent behavior and its consequences can be prevented. Violence is defined as the intentional use of physical force or power, threatened or actual, against oneself, another person, or a group or community that results in or is likely to result in injury, death, psychological harm, maldevelopment,