Book excerpt: Advances in Radiation Biology: Relative Radiation Sensitivities of Human Organ Systems, Part III, is the third volume of the series "Relative Radiation Sensitivities of Human Organ Systems." It presents reviews of organ systems not included in the preceding two parts (Advances in Radiation Biology, Volumes 12 and 14). The subject matter contained in the current volume is viewed through the eyes of the radiation therapist. Although the presentations have strong clinical overtones, an effort has been made, wherever possible, also to address the radiobiological bases of radiation sensitivity of organs. The book contains seven chapters and begins with a study on radiation damage to the kidney. This is followed by separate chapters on inherent or intrinsic radiosensitivity of human cells; the impact of brachytherapy (i.e., short-distance radiation treatment using photon radiation) on tumors; and human tissue tolerance to fast neutron radiotherapy. Subsequent chapters deal with normal tissue effects of combined hyperthermia and radiotherapy; the impact of ionizing radiation on the successive stages of human development in utero; and developments in theoretical knowledge and practical applications of ionizing radiations which have taken place in a little less than a century.