The foundational chapter provides an overview of essential aspects of the phenomenon of domestic violence, including prevalences, gender differences, and criminal classification. The different forms of aggressive behavior are of central practical importance for risk management and safety planning. Therefore, the significance of reactive and proactive aggression in the field of domestic violence is discussed, and other central categories are introduced, such as physical, psychological, sexual, and economic violence. Further focal points of the chapter are digital violence and technology-based sexual violence, as well as stalking and cyberstalking.