This book is divided into four chapters. In first chapter, the introduction to the subject area, some basic definitions and concepts have been discussed with examples to acquaint the reader with the basic terminology used in this book and further divided into six sections: (i) General introduction of the subject, (ii) Seismic waves and its types, (iii) Explanation of Earth's structure and its layers, (iv) Brief explanation of theory of elasticity, (v) Hooke's law and (vi) Porous medium. In second chapter literature survey related to wave propagation in different media have been discussed. In third chapter dispersion equation for model consisting the layers such as: intermediate layer is transversely isotropic liquid-saturated porous layer resting on the non-homogeneous elastic half space which is putting under an elastic isotropic homogeneous rigid boundary and this chapter is divided into seven subsections. In forth chapter conclusion and future scope have been discussed. In the end, a list of the references mentioned at various places in the entire book has been given.