The propagation and behavior of electromagnetic waves is important for semiconductor physics and electrical engineering, as well as for materials science. This unrivalled monograph represents a systematic treatment, including novel research on special topics in the field, such as the peculiarities of the polaritons in anisotropic semiconductors in the presence of mobile charge carriers. Divided into four main sections, the book presents the theory of propagation and excitation of volume and surface electromagnetic waves in anisotropic polar and nonpolar conducting crystals, together with the effects of external magnetic and strong electric fields. It also investigates the spectrum of bulk as well as surface phonon-plasmon polaritons in uniaxial semiconductors, as well as electromagnetic instabilities leading to the generation and amplification of radiowaves. Additional topics include total transmission, magnon-plasmon polaritons, and the influence of hot 2D carriers. Crucial reading for theoretical physicists, IT and electrical engineers, as well as those working in information science.