Ageism is prejudice and discrimination against people on the basis of age and is a social problem that particularly stigmatizes and marginalizes older people. To study age and social inequality, many analysts focus on the life course, which includes the age-based categories through which people pass as they grow older (childhood, adolescence, emerging adulthood, young adulthood, middle age, later maturity, and old age). Age stratification refers to the inequalities, differences, segregation, or conflict between age groups. The problems it creates are most pronounced among older people, who face workplace discrimination, the necessity of retiring at some point, health problems, victimization, and, sometimes, family problems and social isolation. Providing protection from age discrimination is the Age Discrimination in Employment Act of 1967. Within the functionalist perspective, disengagement theory examines the orderly transfer of roles and statuses from one generation to the next. Activity theory is a symbolic interactionist perspective and assumes that older people who are active are happier and better adjusted than those who are less active. From a conflict perspective, class constitutes a structural barrier to older people’s access to valued resources.