Theoretical understanding of electronic properties of metallic alloys is of great importance from both fundamental and technological points of view. All the chapters in this book are developed from the fundamentals and are coherently interrelated in a meticulous manner. The book gives a brief account of the crystal structure of both the pure metals and metals with impurities. Physical effects produced by impurities in metals are described in detail. The electronic structure of pure simple and transition metals is described with special reference to rare-earth metals.