Business projects with very long time horizons--such as those involving product R&D, workplace design, and total compensation planning--have to contend with a crucial question: What will be the needs, demands, and desires of consumers and employees decades from now? If you think the answer is "Just more of the same," you're in for a surprise. Howe and Strauss, the authors of Generations, The Fourth Turning, Millennials Rising, and other books, have studied the differences among generations for some 30 years. Their extensive research has revealed a fascinating pattern--one so strong that it supports a measure of predictability. On the basis of historical precedent, they say, we can foresee how the generations that are alive today will think and act in decades to come. Three of those generations will still be vital forces in American society 20 years from now: Boomers, Generation X, and Millennials. Their attitudes and behaviors will have profound effects on the economy, the workplace, and social institutions in general. For example, as aging Boomers eschew high-tech medicine in favor of holistic self-care, natural foods, and mind-body healing techniques, some hospitals are opening new wings featuring alternative medicine and spiritual counseling. Gen Xers, having grown up in an era of failing schools and marriages, will remain alienated, disaffected, and pragmatic as they enter midlife. Already the greatest entrepreneurial generation in U.S. history, they will be highly effective at pushing innovation, efficiency, and mass customization. In contrast, young adult Millennials will favor teamwork, close family relationships, job security, and a bland popular culture. Their unprecedented digital empowerment and talent for organizing will create a political powerhouse and may even revitalize the union movement.