High-voltage technology is a field of electrical engineering the scientific principles of which are essentially found in Physics and which, by its application, is intimately linked with industrial practice. It is concerned with the physical phenomena and technical problems associated with high voltages. The properties of gases and plasmas, as well as liquid and solid insulating materials, are of fundamental significance to high-voltage technology. However, despite all progress, the physical phenomena observed in these media can only be incompletely explained by theoretical treatment, and so experiment constitutes the foreground of scientific research in this field. Teaching and research in high-voltage technology thus rely mainly upon experimental techniques when dealing with problems. Recognition of this fact is the conceptual basis for the present book. It is primarily intended for students of electrical engineering and aims to provide the reader with the most important tools for the experimental approach to problems in high-voltage technology. An attempt has been made here to indicate important practical problems of testing stations and laboratories, and to suggest solutions. The book should therefore also prove to be a help to the work of the practising engineer. The theoretical considerations are correlated with the experiments of a high-voltage practical course, which are described in great detail. The treatment assumes as much familiarity with the subject as may be expected from 3rd year students of electrical engineering.