A new, consistent set of values for the physical constants has been recommended by the Committee on Fundamental Constants of the National Academy of Sciences—National Research Council. These values were presented to the Second International Conference on Nuclidic Masses held in Vienna, July 15–19, 1963. At the General Assembly meeting of the International Union of Pure and Applied Physics held in Warsaw, September 18–23, 1963, the following statement was adopted: “The Commission [on Nuclidic Masses and Related Atomic Constants] expects that these values will be widely used and will help to remove many of the confusions that have arisen from the use of differing sets of constants. In addition, it is expected that the appearance of this list will encourage further experimental work aimed at improving our knowledge of these values.”