Aging is a near universal process, yet the molecular mechanisms that underlie cellular senescence have remained elusive. Recent progress in determining the roles of various genetic influences in controlling the rate of cellular aging has made this an exciting time in aging research. Genetic screens designed to isolate long-lived mutants in Saccharomyces cerevisiae and Caenorhabditis elegans have implicated factors involved in transcriptional silencing and the dauer pathway in the control of aging. The gene responsible for Werner's syndrome, a disease with symptoms of premature aging, was isolated and found to be a member of the RecQ subfamily of DNA helicases. The regulation of telomere length and its role in senescence and cellular immortalization has been found to be more complex than expected. In C. elegans, mutations have been isolated in maternal-effect genes that presumably control its biological clocks and can dramatically extend its lifespan. Indeed, aging research within the past year has implicated a variety of mechanisms ranging from the control of gene expression, stress resistance, and DNA metabolism to the overall 'rate of living'.