In 1976, the International Union of Theoretical and Applied Mechanics (I.U.T.A.M.) agreed to hold a 1979 Symposium on "Optical Methods in Mechanics of Solids" at the University of Poitiers, France. The Labaratory of Mechanics of Solids at the University of Poitiers, a research team associated with the French National Center for Scientific Research (Centre National de la Recherche Scientifique, C.N.R.S.) was in charge of the organization. The symposium was held at the Ecole Nationale Superieure de Mecanique et d'Aerotechnique (E.N.S.M.A.), from the lOth to the 14th of September. We have the honour of presenting here the proceedings of this symposium. This initiave, taken by I.U.T.A.M., was based on the conviction that the time was favourable to point out in the vast domain of experimental methods in mechanics of solids the considerable benefits of the new techniques that became available through the use of the properties of laser radiation. Our experience has shown the validity of this point of view. A significant number of internationally renowned specialists had, in fact, manifested the wish to participate in this meeting and to be invited to present a paper. For instance, the Scientific Committee, after examining 71 proposed papers, selected for presentation 21 short communications (20 minutes of presentation) in addition to 24 regular communications (35 minutes of presentation) .