This issue of Preventing Chronic Disease (PCD) focuses on a set of concerns that is likely to challenge the public’s creative spirit and resourcefulness for the next 30 years. Public health is the science and art of preventing disease, prolonging life, and promoting physical and mental health. What we are beginning to see is that success in any one of these areas raises new challenges and presents new problems for us to solve in the other areas. For example, advances in science, better nutrition, and improvements in health care have allowed people around the world to live to unprecedented ages. But this blessing of long life presents us with a new set of formidable challenges: soaring rates of dementia and untreated mental health problems among the elderly, a growing burden of chronic illnesses that affects our communities, disturbing problems of elder abuse, and an unparalleled demand for the services of both professional and family caregivers. All progress comes with costs and challenges, but in the 21st century we will experience this burden on a scale and at a speed that we have never seen before. So, we must prepare ourselves.