Advances in the scientific understanding of the aging brain have led to the concept of cognitive aging. Physicians lag in their understanding of cognitive aging, and the public fear of mental deterioration is disproportionate to its true risk. Understanding cognitive aging requires recognition of its biological underpinnings and the functional changes which may result, as well as the variability across individuals through time and within individuals across different cognitive functions such as memory, knowledge, and reaction time. While there is no magic pill such as a vitamin that has been shown to improve our cognition in later life, several factors that are important well before the age of 65 impact subsequent cognitive aging, including education and a lifelong interest in cognitive stimulating activities. Sufficient evidence exists to recommend three interventions in later life: exercise, reducing cardiovascular risk factors, and careful attention to medications. Acceptance of the new paradigm of cognitive aging is essential to promote the quality of life of older people and will have repercussions throughout society.