It took about 30 y after Wilhelm Konrad Roentgen’s discovery of x rays and Henri Becquerel’s discovery of natural radioactivity for scientists in the civilized world to formulate recommendations on exposure to ionizing radiation. We know of these efforts today because the organizations that resulted from the concerns raised in 1928 at the Second International Congress of Radiology still play a role in radiation protection. The organizations are known today as the International Commission on Radiological Protection and, in the United States, the National Council on Radiation Protection and Measurements (NCRP). Today, as we have many times in the past, we honor Dr. Lauriston Sale Taylor, the U.S. representative to the 1928 Congress, for his dedication and leadership in the early growth of NCRP. NCRP’s mission is “to support radiation protection by providing independent scientific analysis, information, and recommendations that represent the consensus of leading scientists.” The developments in science and technology, including radiation protection, are occurring so rapidly that NCRP is challenged to provide its advice and guidance at a faster pace than ever before. NCRP’s role has also expanded as the Council considers newer uses and applications of ionizing radiation in research and medicine as well as the response to nuclear or radiological terrorism. In such a technical world, new areas have been established to deal with the nexus of science and regulation, especially in the United States. Lord Ernest Rutherford supposedly said, “That which is not measurable is not science. That which is not physics is stamp collecting.” I wonder what he would say if he were alive today as now many embrace a new field called “regulatory science.” This term was suggested by Professor Mitsuru Uchiyama in Japan in 1987 and was reviewed in literature published in English in 1996. Some have attributed a similar idea to Dr. Alvin Weinberg, for many years Director of the Oak Ridge National Laboratory. He actually introduced the term “trans-science,” which he defined as the policy-relevant fields for which scientists have no answers for many of the questions being asked. He was influenced by the heavy involvement of the Laboratory in developing methods to assess environmental impacts as mandated by the 1969 National Environmental Policy Act. Professor Uchiyama defined regulatory science as “the science of optimizing scientific and technological developments according to objectives geared toward human health.” In essence, regulatory science is that science generated to answer political questions. This paper will introduce regulatory science and discuss the differences between what some call “academic science” and “regulatory science.” In addition, a short discussion is included of how regulatory science has and will impact the practice of radiation protection and all areas involving the use of radiation and radioactivity.