Terramechanics is the broad study of terrain-vehicle systems. In this book, the complex physical processes associated with the static and dynamic interplay between (powered and towed) wheeled and tracked vehicles with natural and man-made surfaces are analyzed and mathematically modeled. The focus of the book is the technical or engineering problem of predicting the performance of a specific vehicle-terrain system - real or yet to be designed. Performance here includes such things as: -the generalized mobility of a specific vehicle over a given terrain -the trafficability of a terrain to the passage of various types and numbers of vehicles. -traction performance parameters such a tractor drawbar pull and bulldozer blade push -vehicle travel speeds and so on In very logical and systematic manner, the book builds on the basic principles of engineering soil mechanics to develop progressively more complex mathematical models of the behavior of wheel-based vehicle systems. These ideas are then extended into the considerably more complex area of tracked vehicle systems. Much very recent research work has been used in the development of these models and extensive experimental and field research is used to validate them. The book synthesizes a large amount of very recent research work in this field into an integrated whole. Much of this work derives from specialist International Conferences and Proceedings whose contents are often very difficult to find. Specific and unique features of this book include: -a comprehensive treatment of pneumatic and flexible tired systems and -the presentation of a new method for predicting the performance of track type vehicles based on small scale machine modelstudies. - a trafficability of tired or tracked vehicles running on a weak soil or snow