The dramatic increase in life expectancy in the United States and all other developed nations in the 20th century is one of the greatest cultural and scientific advances in our history. Yet, we are woefully unprepared to address the challenges — such as potential conflicts aggravated by generational differences — and take advantage of the opportunities — unleashing the productivity inherent in a healthy elderly population, for example — that stand before us. In this emerging “aging society,” in which those over age 60 will outnumber those under 15, there remains substantial uncertainty about what life will be like for the elderly and, perhaps more importantly, for the middleaged and younger generations that will follow in the footsteps of today’s oldest Americans. With these considerations in mind, in 2008 the MacArthur Foundation established a Research Network on an Aging Society, bringing together 12 scholars from the United States and Europe from a variety of relevant disciplines including economics, sociology, psychology, political science, medicine, public health, demography, and public policy. Our goal is to identify the changes that need to be made in many aspects of American life, including retirement, the workforce, education, and even the design of our future cities, that will enable us to deal with the challenges and take advantage of the opportunities posed by the aging of our society. The task before us is to establish a secure infrastructure for such a society, a revised set of core elements —family, work-force, retirement, churches, political parties, communities, volunteer organizations, and financial entitlements, among others —that will be needed for our future society to function effectively. But first we must understand the realities of the current demographic transition in life expectancy and their implications for American society as a whole. Too much of what passes for knowledge and understanding of aging in America today are beliefs that are completely or partially false —myths, if you like that must be recognized and unpacked.