Examines the evolution over more than 100 years of radiation protection standards & efforts to ensure radiation safety for nuclear workers & for the general public. The risk of exposure to radiation, even in small doses, has aroused more sustained controversy & public fear than any other comparable industrial or environmental hazard, but this was not always so. What was known, & when, & what was done about the dangers of radiation, is a major 20th-century story reflecting a complex interaction of scientific & political issues. Focuses on the programs of the Fed. agencies established to provide protection for those exposed to low-level radiation from activities under their jurisdictions, incl. the AEC & the NRC, as well as the EPA & others. B&W illus.