Middle adulthood is an important developmental period in the life span. The goal of this article is to give an overview about theoretical and empirical work on midlife development. The first part emphasizes the importance of studying midlife development. The second part presents conceptual frameworks and central issues of midlife. The third part summarizes research findings for environmental changes in the primary social contexts and social roles of midlife including family, work, and community. The fourth part summarizes research findings for individual changes in multiple domains such as cognitive and emotional abilities, personality and the self. The final part includes future directions.