The United Nations World Assembly on Aging has made advancing health and well-being into old age a worldwide call for action. And this text at hand shows us what researchers worldwide are doing to answer that call. Here, three of America's most esteemed experts on aging lead a global team of contributors - each an expert in his or her country - to show us what the top challenges of each nation are, and what top research is being done there to meet those. While we cannot predict with absolute certainty all of the issues that will arise over the next 20 years, we can anticipate some and we must start now to prepare for these challenges, an expert from the U.S. Department of Health and Human Services warned at a recent UN World Assembly on Aging. Needed response to the global population shift is not just the responsibility of governments, but will be a product of wise, long-term decisions made by individuals and societies, she explained.