Gerontologist Caleb Finch has a new book out this month, entitled "The Biology of Human Longevity: Inflammation, Nutrition, and Aging in the Evolution of Lifespans." Here, US News takes a gander: "In the last 200 years, one year of extra lifespan has been added for about every four years of historical time. Life expectancy has doubled since the industrial revolution, from about 40 years to near 80 years. ... Aging processes in humans are directly related to the nutritional and inflammatory aspects of the environment. One example is Alzheimer's disease: Research from our lab has shown that the senile plaques that build up in that disease are related to inflammatory processes in the brain. And we now know that inflammation intensifies atherosclerosis, the hardening of the arteries that can contribute to stroke and heart attack. Longer life spans have been a worldwide phenomenon associated with improvements in hygiene and medical care and reductions in infectious disease. Some have explained this through the reduction of infant mortality. But we're also living longer because we're staying healthier - kids have fewer infectious diseases to fight with. This reduction of inflammation and infection, along with the improvement of nutrition, has contributed to longevity by slowing many of the diseases of aging."