Future research on the psychology of nostalgia may benefit from the development of a broad regulatory model of nostalgia. Psychologists have argued that behavior is driven by avoidance and approach action tendencies. That is, people are motivated to avoid unpleasant states and approach pleasant ones. This chapter discusses negative psychological states trigger nostalgia and nostalgia promotes positive psychological states. In other words, nostalgia serves a restorative function and may thus, more broadly, serve an approach/avoidance regulatory function. The chapters hypothesized that nostalgia is a psychological mechanism that serves a motivational regulatory function by counteracting avoidance motivation and facilitating approach motivation. Nostalgia increased feelings of youthfulness. When people engage in nostalgic reflection they experience a boost to positive mood, feelings of connectedness to others, self-esteem, and meaning in life. In addition, nostalgia promotes psychological growth and approach motivation. The book discusses nostalgia at the personal level. That is, when considering the effects of nostalgia, it focuses on the individual.