The VDE series of publications 9 describes the relationships between the effects of current passing through the human body, the possible touch voltage depending on the grounding connections of an electrical installation, and the protective devices that can safeguard individuals in the event of a fault. Only by considering these facts together can an appropriate protective measure be selected. The focus of the discussions in this book is primarily on alternating current circuits. If a comparison with direct current circuits was necessary, it was also addressed. During the development of the book, it was noted that protection against electric shock due to the renewed establishment of direct current systems, for example through photovoltaics or in electrical engineering for electric vehicles and their charging, will require a reevaluation of effects and protective measures in the standards in the future.