This volume brings together scholars of childhood, adulthood, and old age to explore how and why particular ages—such as sixteen, twenty-one, and sixty-five—have come to define the rights and obligations of American citizens. From the colonial period to the present, Americans have relied on chronological age to determine matters as diverse as who can cast a vote, marry, buy a drink, or qualify for a pension. Contributors to this volume explore what meanings people in the past ascribed to specific ages and whether or not earlier Americans believed the same things about particular ages as we do. The means by which Americans imposed chronological boundaries upon the ongoing and variable process of growing up and growing old offers a paradigmatic example of how people construct cultural meaning and social hierarchy from embodied experience. Further, as the contributors to this volume argue, chronological age always intersects with other socially constructed categories such as gender, race, and sexuality. What makes age different from other categories such as whiteness and maleness is that, if we are lucky to live long enough, we will all pass through the chronological markers that define us as first young, then middle aged, and finally old.