In 1997, after more than a decade of research, the National Cancer Institute (NCI) released a report that provided its assessment of radiation exposures Americans may have received from radioactive iodine released from the atomic bomb tests conducted in Nevada during the period 1951 to 1962. This is an evaluation of the soundness of the methodology used by the NCI study to estimate: past radiation doses; possible health consequences of exposure to I-131; implications for clinical practice; and possible public health strategies - such as systematic screening for thyroid cancer - to respond to the exposures. In addition, the book provides an evaluation of the NCI estimates of the number of thyroid cancers that might result from the nuclear testing programme and provides guidance on approaches that the US government might use to communicate with the public about I-131 exposures and health risks.