THE October 1947 issue of the Journal of the Optical Society of America is the largest issue of the journal ever to be published and was specially called the "Pfund Issue". It consists of articles written by Prof. A. H. Pfund‘s former students and colleagues and is a tribute to him on his retirement from active teaching at the Johns Hopkins University. An advance copy of this issue, together with a ‘scrap-book' containing the letters which accompanied the manuscripts of the articles when they were submitted for publication, was presented to Prof. Pfund at the dinner held during the thirty-second annual meeting of the Society in October last. A photograph of Prof. Pfund is on the opening page, and the first of the twenty-three articles in the issue is by Prof. R. W. Wood, who writes on "The Use of Echelette Gratings in High Orders". Two of the articles are actually by Prof. Pfund himself and co-workers, but he was unaware that his colleagues had submitted the papers for a special issue of the Journal. They deal with selective infra-red gas analysers and with optical scattering by dielectric powders. The other articles include : a historical note on the rate of a moving clock by H. E. Ives ; a spark light-source of short duration by J. W. Beams and others ; an optical study of acoustic fields near diffraction edges by J. C. Hubbard and others; and practical methods of making and using multilayer filters by Mary Banning.