The complex phenomenon of aging has been observed in nearly all multicellular organisms that have been studied. The purpose of this proposal is to produce a single panel of biomarkers of aging, based upon rodent animal models. In particular, this proposal responds to the request for a comprehensive statistical analysis designed to bring together the results of all of the research conducted as a part of this Biomarkers of Aging Research RFA (NIH/NIA RFA AG-91-17), using the procedures of mathematical statistics, mathematical modeling, and advanced scientific visualization techniques to permit a statistically, as well as scientifically/biologically valid assessment of the gerontologic age of rodents of the genotype specified in the RFA using a panel of applicable biomarkers of aging. In order to test the effects of potential strategies and interventions, on the extension of the vigorous and the productive years of life, it is important that viable biomarkers of aging be developed. The development of biomarkers of aging is particularly important if a scientific intervention strategy is to be developed for humans.