When working with processes where large plastic deformation occurs, a way of desribing the deformation process is to view the whole deformation history as a curve in the 6-dimensional shear strain normal strain space, henceforth called a strain history curve (SHC). This paper focuses on the SHC concept and the uniqueness of the SHC representation.The SHC may be used to give a useful representation of the total course of the deformation with respect to directions and magnitudes of strains, snd hence the development of the plastic properties, butmay also be used for developing variables describing 3D-plasticity. Adirect use of the SHC, is to measure the yield surface at different points at a SHC, thus establishing data describing the importance of strain rotations or even strain reversals within a process. Two subcases for displaying SHC will be mentioned:The plane strain case and the single sheared case. Here the latter is a superset of plateworking processes and axisymmetrical processes.The origin and use of the SHC in this paper, is to make a method of classifying processes after strain path and hence the need for using advanced plasticity models. As an example the extrusion process is displayed. To quantify a process it is necessary to study strain path for the whole volume. Thereafter these strain paths can be plotted and modelled.