This volume contains the lectures presented at the mini-symposium on "Micromechanics" held in conjunction with the CSME Mechanical Engineer ing Forum 1990 between the 3rd and 8th June, 1990 at the University of Toronto, Canada. The expressed purpose of this symposium was to discuss some recent developments in the Micromechanics of Materials and how ad vances in this field now relate to the solution of practical engineer ing problems. Due to the time limit set for this section of the Engineer ing Forum as well as the restriction on the number of papers to be pre sented, it was not possible to cover a much wider range of topics. How ever, an attempt was made to include the most important advances asso ciated with the progress made in micromechanics in its application to material science and engineering over the past decade. Thus, the topics are concerned with: the fundamental aspects of the thermodynamics of structured solids (part I), - the micromechanical behaviour of alloys (part II), - the modelling of the material behaviour on the basis of continuum theory (part III), and finally the important new approach to the characterization of various mate rials and their responses to external agencies by the use of proba bilistic micromechanics (part IV). We would like to take this opportunity to thank the Chairman of the Organizing Committee, Prof. F. P. J. Rimrott, and the President of the CSME, Prof. T. S."