The book offers systematic dynamic analysis of soils and their engineering applications, including machine foundations, and aims to develop a clear understanding of the subject. It comprises sixteen chapters. Chapter 1 introduces the reader to the various problems in soil dynamics. In Chapter 2, concepts of theory of vibrations are discussed along with their applications in designing Vibration Absorbers and Pickups. Wave propagation in elastic medium including wave refraction in layered medium is covered in Chapter 3. Chapter 4 deals with the procedure of determining dynamic properties of soils using various laboratory and field tests. Dynamic earth pressures in retaining walls and dynamic bearing capacity of footings are dealt with in Chapters 5 and 6 respectively. Chapters 7and 8 respectively deal with dynamic behavior of pile foundations and slopes. Causes of liquefaction of soils and prediction of liquefaction potential have been discussed in Chapter 9. In Chapter 10, the procedure of estimating the unbalanced forces in various types of machines are covered. Chapters 11, 12 and 13 deal with the analysis and design of foundations of reciprocating machine, hammer, and turbo-generators respectively. In Chapter 14, problems of vibration isolation and screening are dealt with. Chapter 15 discusses the analysis and design of reinforced earth wall located in seismic areas. A new concept of a conventional rigid retaining wall having reinforced backfill is presented in Chapter 16, giving complete analysis and design procedure considering seismic forces.