Alzheimer's disease (AD) is the sixth leading cause of all deaths in the United States, and the fifth leading cause of death in Americans aged 65 and older. Whereas other major causes of death have been on the decrease, deaths attributable to AD have been rising dramatically. Between 2000 and 2006, heart-disease deaths decreased nearly 12%, stroke deaths decreased 18%, and prostate cancer-related deaths decreased 14%, whereas deaths attributable to AD increased 47%. An estimated 5.3 million Americans have AD; the approximately 200,000 persons under age 65 years with AD comprise the younger-onset AD population. Every 70 seconds, someone in America develops AD; by 2050, this time is expected to decrease to every 33 seconds. Over the coming decades, the "baby-boom" population is projected to add 10 million people to these numbers. In 2050, the incidence of AD is expected to approach nearly a million people per year, with a total estimated prevalence of 11 to 16 million people. Significant cost implications related to AD and other dementias include an estimated $148 billion annually in direct (Medicare/Medicaid) and indirect (e.g., decreased business productivity) costs. Not included in these figures is the $94 billion in unpaid services to individuals with AD provided annually by an estimated 10 million caregivers. Mild cognitive impairment (MCI) is an important component in the continuum from healthy cognition to dementia. Understanding which individuals with MCI are at highest risk for eventually developing AD is key to our ultimate goal of preventing AD. This report provides information meant to increase an understanding of the public-health impact of AD, including incidence and prevalence, mortality, lifetime risks, costs, and impact on family caregivers. This report also sets the stage for a better understanding of the relationship between MCI and AD.