While the most important radiobiological questions at present can be stated simply, arriving at the answers requires the development of a broad base of understanding to which collaborative interdisciplinary efforts that use a variety of techniques will make important contributions. In spite of the range of questions that remain unanswered, we probably know more about the effects of radiation than any other environmental agent. A sound and well-planned research program into the mechanisms of radiation carcinogenesis can help in many predictable ways. It will provide data needed for setting protection standards, of course, but it will also play a vital role in solving some of the enigmas of the mechanisms of carcinogenesis. In addition, the information gained by the approach focused on basic science will ultimately provide much better methods for extrapolating from cellular and animal studies to health effects in humans and thus for developing sound, science-based radiation risk estimates.