A MOST successful International colloquium on the optical properties of solid thin films was held at Marseille during the week April 19–23 under the auspices of rate Centre National de la Recherche Scientifique. Some forty-four physicists attended by invitation, and, of these, twenty-five contributed papers. There was, of course, a strong contingent from France, including, among others, P. Jacquinot, M. Perrot and P. Rouard. From Great Britain contributions were read by K. M. Greenland, O. S. Heavens, H. Kuhn and S. Tolansky. The United States were represented by B. H. Billings, N. W. Scott, J. Strong and A. F. Turner, the Netherlands by P. van Alphen and B. Blaisse, Italy by M. Ballerini, Switzerland by M. Schaetti and Czechoslovakia by A. Vasicek.