Studies of brain aging have certainly (dare we say it) come of age. The past two to three decades produced a striking increase in experimental investigations of the neurobiological basis of brain aging and of aging-related changes in neural and cognitive function. The public’s interest in experimental gerontology has grown as the public has become more “gray,” with both average age and life expectancy increasing in most developed countries. Driving the specific interest in the aging nervous system is the recognition that increased longevity has little appeal for most unless it is accompanied by maintenance of cognitive abilities. Indeed, if one searches the popular press or the Internet for information on aging, or for products that are purported to slow the aging process or limit its effects, one concludes that maintaining brain function may be the most important concern of older individuals.