Life course studies have ushered in unprecedented scientific interest not only in specific periods of human lives but also in the long-term processes associated with growing older. Studies that link periods of the life course have identified important sources of continuity and discontinuity and highlighted the antecedents of misfortune. Theories and conceptual frameworks have emerged to help scholars splice pieces of the life course together, but the need for conceptual clarity remains. Concepts such as vulnerability and disadvantage are important but used in many different ways by researchers. We pose questions to enhance clarity of these and related terms and call for greater attention to temporal referents in studying the life course. The attention to chronological time-manifest in the identification of age, period, and cohort-is excellent but greater attention to perceptions of time also is needed to better integrate human agency and historical context in studies of life course processes.