The U.S. population is getting older, and Americans are living longer, on average, than they ever have before. As they age, people are healthier and more active than the generations before them and have fewer functional limitations such as difficulty walking or blindness. Studies show that people are happier on average as they advance into their later decades and enjoy high levels of accumulated knowledge and experience. Getting older is a time of social, emotional, mental, and physical change. Retirement might change how a person interacts socially every day, affecting a person’s mood and well-being. Cognitive aging--the normal process of cognitive change as a person gets older--can begin, or a permanent change in physical function may arise. Technology offers a path for people who are navigating these changes potentially to prevent or minimise the risks associated with them and to enhance people’s ability to live their lives fully. The President’s Council of Advisors on Science and Technology (PCAST), seeks to identify technologies and policies that will maximise the independence, productivity, and engagement of Americans in their later years. This book focuses on four key changes older Americans often experience: hearing loss; loss of social engagement and connectivity; cognitive change; and physical change.