The book is devoted both to researchers wishing to acquire a basic knowledge on the optimization of complex mechanical systems and to engineers specialist in the field of vehicle design. In the introductory chapter, the main optimization problems issues are briefly presented without resorting to involved mathematics. Therefore the reader is aware of what is actually the optimization of complex systems and the actual problem solving capabilities available. All of these topics are dealt with in a complete mathematical form in the second part of the book. In the third part of the book, a number of relevant optimization problems referring to ground vehicles are solved, whenever possible, in analytical form. The best compromise between handling, road holding and comfort of road vehicles is studied using validated full non linear models. The optimal design of railway vehicles is dealt with. Additionally the design of springs and other vehicle sub-systems are reinterpreted making use of the presented optimization theories and may bring new ideas for future applications. Though the optimization of complex mechanical systems will be continuously updated in the near future, the book will remain informative both with reference to theory presented, and with reference to those optimization examples which pertain to engineering science. Giampiero Mastinu, Ph.D., professor of Vehicle System Engineering at the Politecnico di Milano (Technical University), Italy Massimiliano Gobbi, Ph.D., professor of Optimal Design at the Politecnico di Milano (Technical University), Italy Carlo Miano, Ph.D., research engineer at the Ferrari Formula 1 Team, Maranello (Modena) Italy.