Our objective was primarily to consider in a separate treatise from the general point of view a theory of as many electrodynamic phenomena in a magnetic field as possible. The choice of material was determined by both the ab- sence of such a book and the scientific interests of the authors. From the very beginning, however, we felt it necessary to include the fundamentals of electrodynamics that are required for the thorough analysis of particular processes. We believe that it is convenient for a reader to find in the same book a consistent review of some special fields in physics and a...