The material contained in this volume is united by common methods and ideas: the Earth's interior is treated as a continuum within the scope of classical physics. Such an approach is considered to be basically sufficient for the majority of the fundamental problems of the physics of the Earth's interior. Using modern methods of continuum mechanics and experimental data, it is possible to construct models of and theories about the dynamic processes taking place in the Earth's interior. The theories and models presented in this volume are supplemented by numerous applications to seismology (in particular earthquake physics), thermal convection of the Earth's interior, magnetic-field generation and a series of other geophysical problems. The theories and models concerning continuous media reviewed here are important for a sound understanding of the physical processes and dynamics of the Earth's interior. The authors have used the latest original results and present the elements of the theories in a concise, monographic form, referring to the abundant literature on the subject.