This book presents a unified approach to the electrodynamics of continua, based on the principles of contemporary continuum of physics. This interdisciplinary approach is unique for the treatment of the subject matter, and much of the material is new or newly composed. No other treatise similar in content and composition to this one exists at this time. The authors present a self-contained, finite deformation and finte electro-magnetic field theory from a unified viewpoint, providing ample critical illustrations by way of applications. The constitution of the book is as follows: (1) development of the ten basic balance laws in order to establish the macroscopic electromagnetic theory; (2) establishment of the general constitutive theory. By means of eight axioms, the local nonlinear theory is developed for finite deformations and E-M (electromagnetic) fields. In this way, for the first time, it has been possible to express the nonlinear constitutive equations for the ninety magnetic groups relevant to magnetic crystals. (3) discussion of special theories and applications. Various special topics are explored and solutions presented to several nonlinear problems in order to demonstrate the uses of the basic theory. The book is intended primarily as a guide and reference for researchers, although selected chapters can well be used as a textbook for graduate studies.