This textbook presents a detailed description of basic semiconductor physics, covering a wide range of important phenomena in semiconductors, from simple to advanced. It introduces and explains four different methods of energy band calculations in the full band region and covers fundamental topics such as the effective mass approximation and electron motion in a periodic potential, the Boltzmann transport equation, and deformation potentials used for the analysis of transport properties. The text also examines experimental and theoretical analyses of cyclotron resonance in detail and reviews essential optical and transport properties, while covering optical transitions, electronβphonon interaction, and electron mobility. It presents numerical calculations of scattering rate, relaxation time, and mobility for typical semiconductors with bulk, quantum well and HEMT structures including wideband gap materials such as GaN and SiC in addition to IV and III-V semiconductors. The updated fourth edition includes coverage of new topics such as surface-modulated superlattices, WannierβStark effect, Bloch oscillation, wide band gap semiconductors, and photonic crystals. Featuring full-color diagrams calculated with updated physical parameters, as well as chapter-end problems and solutions, this tried and tested textbook on the basics of semiconductors physics is the cornerstone to any graduate or upper-level undergraduate course on the subject.