The discovery that the transition to adulthood is increasingly complicated and extended has prompted many social scientists to see it as a distinct phase in the life course. But while scholars have learned a great deal about the objective dimensions of this new "young" or "emerging" adulthood, we know very little about how it is understood and experienced by young people themselves. This paper begins to fill that gap, drawing on a new battery of intensive interviews with selected participants in the University of Minnesota's Youth Development Study (YDS). Focusing on respondents' subjective conceptions of adulthood, understandings of conventional milestones, and visions of aging and success, we suggest that young people today see themselves entering a new phase of life - a dynamic, constantly unfolding package of social roles and personal qualities. This "new adulthood" is seen as an alternative to and improvement on the static, stoic, and stagnant adulthood of their parents' generation, although whether it is seen as a new and distinct phase in the life course remains open to question. These findings not only capture the expressed understandings of adulthood emerging among those in their late twenties, but also allow us to reflect on recent economic and cultural transformations in the postindustrial United States.