The Symposium on the Photoelastic Effect and its Applications sponsored by IUTAM with the cooperation of the Permanent Committee for Stress Analy- sis and the Society for Experimental Stress Analysis was convened at IBM Ed- ucational Center, Ottignies, Belgium, September 9-14, 1973. The subject of the Symposium was the study of the interaction of matter with light in a broad sense. More specifically three main subjects were proposed: (1) Classical and advanced photoelasticity (2) Rheooptics and (3) Theoretical mechanics of a continuum in interaction with the electro-mag- netic field. For a...