THIRTY-NINE papers are covered in the recently published “Abridged Scientific Publications from Kodak Research Laboratories”(vol. 19. Pp. viii + 288. Rochester, New York: Eastman Kodak Co.). The wide variety of subjects studied at the Kodak Laboratories is well illustrated. Most of the papers have some obvious connexion with photographic manufacture or technique. Among these may be mentioned specially four papers dealing with the measurement of photographic density. This has never yet been standardized and, though for most technical purposes ‘density’ is sufficiently well understood to permit useful application of measurement to laboratory testing and works control, yet for precise comparison of results obtained on different instruments of slightly different design, there is need for much further progress. Perhaps the new information may be useful in achieving this. There are, however, several papers which are devoted to subjects which are outside the photographic field altogether, and here we may cite a group of papers by Dr. K. C. D. Hickman and colleagues dealing with fractional distillation of phlegmatic liquids. The work has resulted in development of much improved apparatus for distillation of vitamins. As with previous volumes, each paper is presented without drastic shortening, so that to those who are not able to turn to the full papers in their original journals the volume is of exceptional value.