The theory of plasticity has a broad range of applications in industry and engineering. Its methods permit to devise metal processing, allow to assess safety of structures against collapse, make possible to estimate flow of bulk solids. The technological progress calls both for deeper understanding of sources of plastic deformation and for more rigorous description of mecha nisms of plastic motion. It was felt at the Institute of Fundamental Technological Research in Warsaw several years ago that an international meeting bringing together experts in various domains of plasticity and studying...