Model characteristics of a life-span approach to the study of psychological aging are reviewed. Focusing on a selected set of model attributes related to the tasks of describing, explaining, and modifying intraindividual and interindividual patterns of development and aging (continuity vs. discontinuity of antecedent-consequent relationships, concurrent vs. historical paradigms, time-lag relationships, treatment by history interactions, etc.), a number of questions prototypical of a life-span view of aging are derived. The primary conclusion is that a life-span view of aging redirects conventional thinking about psychological aging as a fixed decrement phenomenon toward a systematic analysis of the aging process in terms of dynamic and interactive man-environment systems and a more variable view of the aging process relative to its form and directionality. Furthermore, it facilitates the conceptualization of prevention efforts aimed at optimizing the aging process in a changing society.