© Springer International Publishing 2016. Aging is not a disease. It is a generalized and progressive loss of function with the passage of time that makes us increasingly vulnerable to a broad suite of diseases. The Geroscience Hypothesis asserts that any intervention that retards the aging process will simultaneously delay the onset of multiple diseases. Retarding the aging process is not only a worthwhile medical enterprise; it is achievable as shown by the fact that nature has achieved it many times. Humans, for instance, age about half as fast as their close evolutionary relatives, chimpanzees. Experimentally, dietary restriction retards aging in a variety of laboratory organisms. Dietary restriction not only increases longevity, but it also slows the rate of functional decline in many systems, delays multiple chronic diseases, and has been repeated in multiple laboratories in multiple genotypes. In addition, direct manipulation of dozens to hundreds of individual genes also appears to slow aging, as indicated by a life-lengthening effect. The knowledge gained in genetic studies has now been employed to design pharmacological interventions. The National Institute on Aging’s Interventions Testing Program has been phenomenally successful at discovering compounds that extend life in genetically heterogeneous mice. Five compounds that extend life in at least one mouse sex have been reported to date, suggesting the real possibility that successful interventions in the aging process can be developed for humans.