This book conveys the theoretical and experimental basics of a well-founded measurement technique in the areas of high DC, AC and surge voltages as well as the corresponding high currents. Additional chapters explain the acquisition of partial discharges and the electrical measured variables. Equipment exposed to very high voltages and currents is used for the transmission and distribution of electrical energy. They are therefore tested for reliability before commissioning using standardized and future test and measurement procedures. Therefore, the book also covers procedures for calibrating measurement systems and determining measurement uncertainties, and the current state of measurement technology with electro-optical and magneto-optical sensors is discussed.