One hundred and twenty two years, as far as we know, is the longest that anyone has ever lived. A woman in France, Jeanne Calment, reached the age of 122 years in 1997, according to details provided by her retirement home. No precise cause of death was recorded.

Those "blessed" with long lives always make us wonder: What is the secret? Does it lie in the genes? Is it where people live or the way they live -- something they do or do not do? Eat or do not eat?  Is the human lifespan something that with modern technology we can extend?

Did Jeanne Calment approach some built-in, biological limit? Is there a maximum human life span beyond which we cannot live no matter how optimal our environment or favorable our genes?

Whether or not there is such a limit, what happens as we age? What are the dynamics of this process and how do they make life spans short, average, or long? With an understanding of these dynamics, can we use this understanding to extend the human life span to 120 or even, as some scientists speculate, to much greater ages?

And finally, but potentially most importantly, how can insights into longevity be used to fight the diseases and disabilities associated with old age to make sure this period of life is healthy, active, and independent?