This paper presents the "uses of the past" model of personality development, a model in which adult development transforms an individual's history into resources for meeting present demands. The components of the model are delineated in terms of how: (1) neither the past nor the present is fixed in its effects or its contribution to present adaptation; (2) experiences of the past and present interact; and (3) the past, as it expands over time, allows new combinations and capacities for later life changes. Adulthood is defined not as an unchanging stage, but as a series of ongoing states that recruit and combine material from the past for present effective functioning. To illustrate the model, longitudinal data from two inter-generational studies are presented in which subjects' past modes of responding are correlated with adult adaptation according to relevance rather than recency. Findings from the studies are discussed, and future research of and uses for the model are suggested. (NRB)