ALTHOUGHthere were no singularly outstanding contributions in techniques or in instrumentation during the past year, real progress has been made in electron microscopy as an applied science. Most critical investigators have stopped worrying about pushing resolution to the very ultimate-say 5 to 10 A. In general, the electron microscope is now being used for the chief purpose for which it was originally intended, the examination of structure improperly resolved in a light microscope. Certainly theory (15, 17-19, 67) and instrumentation (9,55,56,58,61,62,64,65,73,76) are still under consideration; this is as it should be. However, the most gratifying development during the past year has been the reports of the applications of electron microscopy to important long-range research problems with subsequent more affirmative explanations offered for the solutions to these problems. There is much less concern