[en] Essential information on the health protection of radiation workers which has accumulated since the advent of nuclear fission thirty years ago is presented in simple terms. Basic facts on ionizing radiation, its measurement, and dosimetry are presented. Acute and chronic somatic and genetic effects are discussed with emphasis on prevention. Radiation protection standards and regulations are outlined, and methods for maintaining these standards are described. Diagnosis and treatment of radiation injury from external radiation and/or internally deposited radionuclides is considered generally as well as specifically for each radioisotope. The medical supervision of radiation workers, radiation accidents, atomic power plants, and medicolegal problems is also covered. (853 references) (U.S.)