The subject of electronic and ionic materials has grown rapidly over the last 20 to 30 years. The application of these materials has had a significant impact on modern industries and on society in general. The subject is so important that no electrical engineering, materials science and engineering, applied physics or chemistry degree would be complete without it.This valuable textbook is aimed at engineering and technology undergraduates who have a background in physics or chemistry only at first year level. It provides a basic understanding of the properties and uses of a wide range of electrically and ionically conducting materials. It is not intended to be a solid state physics or chemistry book, and so the mathematics is kept to a minimum. However, it is intended to give the student an overview of a wide range of electrical materials and their uses in today's society.