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 plastic behavior from different positions could be of use for further development of the discipline itself and for its service to society. The appropriate occasion for such a meeting sponsored by the Polish Academy of Sciences was provided by the 70th anniversary of Professor Wadaw Olszak. The idea of a fundamentals oriented symposium was favorably received by the scientific community over the world. Eminent scientists generously advised me as to the scope of the meeting and helped in shaping the program. It was eventually decided to concentrate the debates on a) physical foun­ dations of plasticity , b) thermodynamics of plastic and visco-plastic deform­ ation, c) experiments regarding plastic behavior, d) mathematical methods in plasticity, e) computer techniques suitable for solving important techno­ logical problems. The selection of papers was made accordingly. The symposium contributed papers were published in the volume entitled 'Foundations of plasticIty' and in the 'Archives of Mechanics' No.3, 1972.

List of contents.- Invited lectures.- Limit analysis : the development of a concept.- On plastic analysis of the microstructure of metallic alloys.- Lattice defect approach to plasticity and viscoplasticity.- Representation of elastoplastic behavior by means of state variables.- Elastic-plastic theory at finite strain.- Director vectors and constitutive equations for plastic and viscoplastic media.- Internal variable description of plasticity.- The microdynamics of plastic flow.- Experimental plasticity. Some thoughts on its present status and possible future trends.- Mathematical methods in plasticity theory.- Computer solutions of plasticity problems.- Rate-type constitutive equations in dynamic plasticity.- Superplasticity : the behaviour and uses of ultra-fine grain alloys.- Constitutive laws for granular media.- Discussion notes.- An axiomatic approach to the theory of thermomechanically constrained materials.- Basic underwater explosive forming systems.- Distributional aspects of the theory of plastic time dependent phenomena.- Boundary value problems with incremental plasticity in granular media.- On objective stress-rate in the constitutive relation for elasticplastic solids.- Extremum principles in the dynamics of rigid-plastic bodies and mathematical programming.- Plasticity analysis in soil mechanics problems.- A note on the behaviour of hardening - softening granular media.- Some remarks on the strain-rate sensitive behavior of shells.- On shakedown criteria.- Comment on elastic and plastic rotations.- A minimum principle in dynamics of elastic-plastic continua at finite deformation.- A note on displacement bounding techniques for dynamically loaded inelastic structures.- Optimal design criteria for reinforced plates and shells.- Coupled thermo-plastic problems.- Un exemple de non validité de la théorie classique des charges limites pour un système non standard.- Elastic-plastic transition.- The constitutive aspects of aging metals.- Formulation of some homogeneous thermodynamic processes as variational inequalities.- Stable growth of a crack in a rate-sensitive Tresca solid.- Discussions to papers contributed.- Static and dynamic elasto-plastic analysis by the method of finite elements in space and time.- Theory of probability and limit analysis of structures under multiparameter loading.- Sur le comportement élasto-plastique et viscoplastique des monocristaux et polycristaux métalliques de structure cubique à faces centrées.- Yield under high hydrostatic pressure.- Plane waves in elastic-plastic solids.- An analytical model of large deformation effects in crystalline aggregates.- On the thermodynamic states of plastically deformed solids.- Some experimental investigations of the elastic-plastic wave propagation in bars.- Finite-strain theory of inelastic behavior of crystalline solids.- On large elastic-plastic deformations.- Microstress fields of slip bands and inhomogeneity of plastic deformation of metals.- A shakedown matrix theory allowing for workhardening and second-order geometric effects.- A description of workhardening of metals with application to variable loading.- Recent advances in optimal plastic design.- Subsequent yield surface determined in consideration of the Bauschinger effect.- Experimental study on one type of plastic anisotropy not considered in simplified flow theories.- Some solutions for a class of plastic-elastic solids.- Comportement élasto-plastique des milieux granulaires.- Fundamental relations of plasticity derived from hypo-elasticity.- Observed plastic behavior of metalsvis-a-vis the endochronic theory of plasticity.- Composite and overlay models in numerical analysis of elastoplastic continua.- Referees.- Symposium Participants.