What does it mean to age: it is not simply the process of growing weaker, acquire strength as we age; suggests an increase in positive attributes of aging, accumulating knowledge and experience (wiser, aging necessarily means deteriorating. Can be thought of as a set of lenses for viewing actions and interactions. To help us make sense of what we observe. Can be used to help a researcher choose his or her research methods, questions, and the sample to focus on. To construct explicit explanations that account for empirical findings. A set of lens for viewing actions and interactions: theory vs. other aspects of knowledge. Steps in thinking about theories: statements describing regularities detected in the process of systematic observations. Similarities are observed: prototypical models are formed which attempt to depict how empirical generalizations are related to each other. Generalizations are made: empirical generalizations and models are accumulated and use to form theories. Theory is made: theory in gerontology.