In 1896, Becquerel announced the discovery of radioactivity. By 1913, Soddy had demonstrated the existence of radioactive species, indistinguishable chemically but with different half-lives and atomic weights, which he named isotopes. The Joliot-Curies made the first artificial radioisotope (30P) by bombarding aluminum with alpha particles. The development of the cyclotron and other high-energy particle accelerators in the early 1930’s led to the production of numerous radioisotopes in measurable quantities. Prior to this, other than use as a physical research tool, the only applications of the radioisotopes were the use of radium and radon for some types of medical therapy and for the production of fluorescent paints for watch dials, etc. Now applications were of sufficient variety and amount to extend their use in many new areas of research and applications. The discovery of nuclear fission by Hahn and Strassmann and the analysis of the implied energetic relations by Meitner and Frisch, just 20 years after the first disintegration of the nucleus by Rutherford, led to the concept of a nuclear chain reaction, which came to fruition in the West Stands Laboratory in 1942. By the beginning of the 1950’s, with the abundant neutron fluxes available at the U.S. Atomic Energy Commission reactors, radioisotopes of many species really became abundant. Naturally occurring radioactive lead had been used very sparingly as tracers as far back as 1918 in determining chemical solubility and in 1923 in plant uptake from lead solutions. Now many new uses were developed and tested as tracers in medical diagnosis, agricultural, and industrial chemical and metallurgical processes. Many theraputic applications were tested. The industrial labs developed thickness and level gauges for control of various manufacturing processes. Cobalt gamma-ray irradiators were developed for medical therapy and have also been used for sterilization of surgical instruments and materials, for food preservation, and for initiation of certain chemical reactions. The most significant development in the 1960’s was the rapidly increasing role of private industry in taking over the development, production, sales, as well as research, into new methods of production and applications of radioisotopes.