The accomplishment of large scale release en erg y m arks an especially appropriate of atomic time for the republication of this volume. The Symposium in 1942 at Rutgers University coincided with the beginning of the final"all-out''effort to complete the development under the cover of the war. The bombs which exploded over Hiroshima and Naga- saki are heralded as opening the new Atomic Age. Actuallv thev were only one suectacular result of the discoveries and patient work or many scientists in laboratories all over the world working for well over fifty years·The unprecedented cooperation among science, industry, and government during the war which made possible the great progress toward practical utilization of atomic energy has shown what can be accomplished when we work together to achieve a common end.