Severe plastic deformation (SPD) is used to convert traditional coarse grain metals and alloys into ultrafine-grained (UFG) materials. UFG materials possess a number of improved mechanical and physical properties which destine them for a wide commercial use. However, any attempt to use SPD technology commercially requires a better insight into the mechanics and practicality of SPD processes. This paper looks into historical development of SPD processes and focuses on such aspects of SPD as material flow, role of hydrostatic pressure, friction, geometry of tools, billet and feeding considerations, technical feasibility, etc. The discussion of these topics sets a background for decisions concerning further research and commercialisation of SPD.