The book has been written in a lucid and systematic manner with necessary mathematical derivations, illustrations, examples and practise exercises providing detailed description of the materials used in electrical and electronics engineering and their applications. Beginning with the atomic structure of the materials, the book deals with the behaviour of dielectrics and their properties under the influence of DC and AC fields. It covers the magnetic properties of materials including soft and hard magnetic materials and their applications. The text discusses fabrication techniques and the basic physics involved in the operation of the semiconductors, junction transistors and rectifiers. It includes detailed description of optical properties of the materials (optical materials), photovoltaic materials and the materials used in lasers and optical fibres. It also incorporates the latest information on the materials used for the direct energy conversion and fuel cell technologies.