Texturing processes are essentially concerned with introducing bulkiness into continuous-Filament (CF) yarns. This means CF yarns generally are the starting material for the texturing processes. However, some melt-spun CF yarns can be textured during their extrusion by special modifications to the melt spinning. Before describing the various principles of texturing it is useful to first consider what is meant technically by continuous-Filament yarns and outline the commonly used raw materials converted into such yarns.