The overall objective of the proposed activity is to acquire, by purchase or otherwise, death index records from the 56 U.S. registration areas for compilation into a consolidated death index covering some period of time prior to 1979. The consolidated file will be for the direct use and benefit of the government and will be maintained and operated by the government, either directly or through the services of a contractor. The file will be used by epidemiologists, both intramural and extramural, for the purpose of determining the vital status of study subjects. Such subjects are followed to determine the health effects of exposures or events which have occurred at some time in the past.