The paper evaluates the economic value of health and longevity improvements using an economic framework based on individuals' willingness to pay. It analyzes historical and potential future gains from reduced mortality risks, focusing on life expectancy and progress against diseases. Over the 20th century, life expectancy increased by about 30 years, with cumulative gains worth over $1.2 million per person. From 1970 to 2000, increased longevity added about $3.2 trillion annually to national wealth, with half attributed to progress against heart disease. Reduced mortality from heart disease alone increased the value of life by about $1.5 trillion per year since 1970. Future health improvements could yield enormous gains, such as a 1% reduction in cancer mortality being worth nearly $500 billion. The authors develop an economic model to value health improvements, distinguishing between health that extends life (type-G) and health that improves quality of life (type-H). They show that health improvements are complementary, meaning progress against one disease increases the value of progress against others. For example, advances against heart disease have increased the value of further progress against cancer and Alzheimer's. The social value of health improvements is influenced by population size, average income, health levels, and age distribution. The paper also highlights the importance of valuing health improvements in the context of medical research and health care expenditures. It argues that health-related investments are crucial for economic growth and that the value of health improvements is often higher than the costs of health care. The analysis shows that the value of a life-year is age-dependent, rising and then falling as a person ages. The value of health improvements is also influenced by the elasticity of intertemporal substitution and the shadow value of non-market time. The study concludes that health improvements are complementary, with mortality-reducing advances increasing the value of further health progress. The value of health improvements is also influenced by the age distribution of the population and the level of health. The paper provides empirical evidence on the value of health improvements and their potential future gains, emphasizing the importance of health research and investment in improving health and longevity.The paper evaluates the economic value of health and longevity improvements using an economic framework based on individuals' willingness to pay. It analyzes historical and potential future gains from reduced mortality risks, focusing on life expectancy and progress against diseases. Over the 20th century, life expectancy increased by about 30 years, with cumulative gains worth over $1.2 million per person. From 1970 to 2000, increased longevity added about $3.2 trillion annually to national wealth, with half attributed to progress against heart disease. Reduced mortality from heart disease alone increased the value of life by about $1.5 trillion per year since 1970. Future health improvements could yield enormous gains, such as a 1% reduction in cancer mortality being worth nearly $500 billion. The authors develop an economic model to value health improvements, distinguishing between health that extends life (type-G) and health that improves quality of life (type-H). They show that health improvements are complementary, meaning progress against one disease increases the value of progress against others. For example, advances against heart disease have increased the value of further progress against cancer and Alzheimer's. The social value of health improvements is influenced by population size, average income, health levels, and age distribution. The paper also highlights the importance of valuing health improvements in the context of medical research and health care expenditures. It argues that health-related investments are crucial for economic growth and that the value of health improvements is often higher than the costs of health care. The analysis shows that the value of a life-year is age-dependent, rising and then falling as a person ages. The value of health improvements is also influenced by the elasticity of intertemporal substitution and the shadow value of non-market time. The study concludes that health improvements are complementary, with mortality-reducing advances increasing the value of further health progress. The value of health improvements is also influenced by the age distribution of the population and the level of health. The paper provides empirical evidence on the value of health improvements and their potential future gains, emphasizing the importance of health research and investment in improving health and longevity.