This dissertation develops a new model of musical affect that consists of (1) a fresh examination of the psychology of music-affective experience, (2) a music-analytical methodology that explores how musical structure shapes that experience, and (3) a report on experiments designed to evaluate various hypotheses regarding music-affective experience. My study begins with a critique of philosophers' and psychologists' definitions of affect and musical affect and goes on to demonstrate that such categories cannot be defined by necessary and sufficient conditions. The analytical methodology models moment-to-moment affective intensity and builds on the principles of the implication-realization model. Musical parameters are shown to function both closurally and nonclosurally. By assigning weighted values to each parameter, I produce numerical and graphical representations of the total closure and nonclosure at each musical moment. Closure and nonclosure determine the moment-to-moment intensity, that is, the strength of affect at each moment in a piece. The results allow statistical evaluation of the relative importance of each parameter for the generation of affect. Empirical results demonstrate that the analytical machinery generates predictions highly similar to subjects' responses. As important as moment-to-moment affect might be, it does not generally determine whether listeners choose to repeat musical experiences. Rather, affective memory guides our future actions. Building on Daniel Kahneman's research, I conducted an experiment designed to explore how listeners calculate remembered affect from moment-to-moment affect. Subjects rate affective intensity and quality both during and after each musical selection. Results demonstrate that music-affective memory distorts affective experience in consistent ways. At least three factors determine how significantly a given moment will impact affective memory: (1) recency, how long ago that moment occurred, (2) intensity, how strong the affect was at that moment, and (3) slope, how the intensity of that moment relates to the same of the preceding moment.