This excerpt from Andrew J. Scott's The Longevity Imperative explores the implications of increasing lifespans for individuals and societies. Scott argues that longer lives require a shift from a disease-focused healthcare system to one that prioritizes health and prevention, particularly through a focus on aging well. He emphasizes the need for a "longevity imperative," which focuses on extending healthy lifespans and avoiding a "Struldbrugg" scenario, where individuals live long but unhealthy lives. The book explores the economic and social implications of these changes, including the need for new models of work, retirement, and pensions, as well as the challenges of generational equity. Scott concludes that embracing the longevity imperative is crucial for achieving a future where long life is also a good life.