“Radioactivity—An Introduction,” is the first Symposium sponsored by ASTM Committee E-10 on Radioactive Isotopes. The Symposium was held in Atlantic City on June 30, 1953, for the purpose of calling attention to the possible utilization of radioactive isotopes in ASTM work. In his opening remarks, the Symposium Chairman noted: “It is a particularly healthy sign to see so many technical people interested in atomic energy and radioactivity. Ever since Hiroshima, the man on the street has been almost more excited about atomic energy than the average scientist. He wanted to use it for everything from powering his automobile to locating his lost golf balls. But most of the ideas put forth were impractical because the right facts about atomic energy were not in the hands of the right people. A noted scientist has caricatured the type of atomic energy publicity that the American people received during the years immediately after Hiroshima as the ‘Einstein to housewife’ approach. It is no wonder there have been so many misconceptions regarding atomic energy. This Symposium is an effort to develop information for those who are in a position to put it to practical use. Through it I am sure we will have a clearer picture of what radioactivity techniques are and whether they have a useful place in ASTM work.” Don M. McCutcheon, Chairman of Committee E-10, then reviewed the history, aims, and activities of the committee. Briefly summarized, Committee E-10 was formed early in 1951 with five major objectives: (1) to promote the knowledge of the use of radioactive isotopes in materials testing; (2) to aid and advise technical committees of the Society in the preparation of methods and development of instruments of testing in the field of radioactive isotopes; (3) to prepare test methods that use radioactive isotopes that do not come within the scope of any other technical committee; (4) to standardize, in cooperation with other committees, the nomenclature of testing methods or instruments that use radioactive isotopes; (5) to perform such other functions as may advance, improve, standardize, and unify the procedures of materials testing by means of radioactive isotopes.