This book offers insight into the current state of investigation into the genetic basis of aging and longevity. It has been written by scientists at the forefront of their field, thus providing a cross-section of current research. The topics covered include work with model organisms such as yeast, fruit flies, the nematode C. elegans, and mice. The most recent findings on the genetics of centenarians and the link between reproduction and life span in humans are also treated. The level of investigation ranges from the identification of life span determining genes by classic epidemiological methods to direct manipulation of rates of aging by molecular biological techniques in the most experimentally tractable systems. Further, it critically examines the significance of some lines of investigation and highlights those theories which may be most capable of providing a synthetic view of current data in the field of aging.