Twentieth-century advances in protecting and promoting health among older adults have provided many opportunities for overcoming the challenges of an aging society. The health indicators presented in "The State of Aging and Health in America 2013" highlight these opportunities. By working to meet the goals for each of these key indicators, our nation can help to ensure that all of its citizens can look forward to living longer and living well. "The State of Aging and Health in America 2013" provides a snapshot of our nation's progress in promoting prevention, improving the health and well-being of older adults, and reducing behaviors that contribute to premature death and disability. In addition, the report highlights mobility (referring to movement in all of its forms) and how optimal mobility is fundamental to healthy aging. The growth in the number and proportion of older adults is unprecedented in the history of the United States. Two factors-longer life spans and aging baby boomers-will combine to double the population of Americans aged 65 years or older during the next 25 years to about 72 million. By 2030, older adults will account for roughly 20% of the U.S. population. During the past century, a major shift occurred in the leading causes of death for all age groups, including older adults, from infectious diseases and acute illnesses to chronic diseases and degenerative illnesses. More than a quarter of all Americans and two out of every three older Americans have multiple chronic conditions, and treatment for this population accounts for 66% of the country's health care budget. "The State of Aging and Health in America 2013" focuses on several areas of concern that, if effectively addressed, will significantly improve the quality of life for older adults.