The observation that “my memory is not so good as it used to be” is one of the commonest complaints of older people. This feeling of mild impairment is typically frustrating and irritating rather than alarming, given the nature of the forgotten information: people’s names elude the would-be rememberer, older adults become “forgetful” about intentions or about where they left their keys or a book, details of experiences are difficult to recollect, and they confuse the source of recently acquired pieces of information. The purpose of the present chapter is to review some of the scientific evidence on this topic. In general, these everyday observations are supported by the results of experiments designed to measure various aspects of memory more precisely. Mild impairment of memory functioning associated with aging is not a myth, unfortunately, and in my opinion it is not an “adaptation” by the older brain to prevent the older mind from being swamped by a lifetime’s worth of trivial experiences. It is a genuine impairment of cognitive functioning. It would be surprising, in fact, if this were not the case, given that the brain is a physical organ like the heart, liver, lungs, and muscles-all of which decline somewhat in efficiency in the course of normal aging.