Before embarking on the focus of this book it was felt necessary to provide a basic understanding of the dynamic forces experienced by any road vehicle during normal operation. This chapter introduces such forces on a vehicle when considered as a rigid body. It discusses the source of each force in some detail and how they may be applied to predict the performance of a vehicle. It extends the normal straight-line driving to include non-steady state cornering and the case of car-trailer combinations. Each section generally includes typical problems with detailed solutions.