This book fills the gap by systematically present the basic principles, theories, materials and their performance, advanced characterizations, design criteria of novel thermoelectric materials and devices as well as their practical applications. It covers a wide range of modern thermoelectric materials from Si, binary alloys to complex oxides and also envelopes a broad range of approaches from bulk to one-dimensional nanostructured materials. This book: 1) correlate the effects of composition, atomic arrangement, electronic band structure, magnetism, electron-electron and electron-phonon interactions on thermal performance of advanced thermoelectric materials; 2) reveals the physics and chemistry underlying the thermoelectric behavior so that the full potential, as well as the fundamental limits, of thermoelectrics can be assessed; and 3) provides detailed information on the materials in various systems and the important issues relating to their thermophysical properties and practical applications.