This paper develops an economic framework to value improvements in health and life expectancy based on individuals' willingness to pay. The authors apply this framework to historical and prospective reductions in mortality risks, both overall and for specific diseases. They find that the social value of increased longevity over the 20th century was over $1.2$ million per person for both men and women. From 1970 to 2000, gains in life expectancy added about $3.2$ trillion per year to national wealth, with half of these gains attributed to progress against heart disease alone. Even modest progress against major diseases, such as a 1% reduction in cancer mortality, would be worth nearly $500$ billion to current and future generations. The potential gains from future innovations in healthcare are also significant, highlighting the substantial economic benefits of improving health and longevity.This paper develops an economic framework to value improvements in health and life expectancy based on individuals' willingness to pay. The authors apply this framework to historical and prospective reductions in mortality risks, both overall and for specific diseases. They find that the social value of increased longevity over the 20th century was over $1.2$ million per person for both men and women. From 1970 to 2000, gains in life expectancy added about $3.2$ trillion per year to national wealth, with half of these gains attributed to progress against heart disease alone. Even modest progress against major diseases, such as a 1% reduction in cancer mortality, would be worth nearly $500$ billion to current and future generations. The potential gains from future innovations in healthcare are also significant, highlighting the substantial economic benefits of improving health and longevity.