Scholarship on ego integrity is rooted in Erik Erikson’s complex theory of life-cycle development and has spread from its origins in psychoanalysis through the disparate fields of life-span human development, age and culture studies, medical humanities, aging services, and beyond. Erikson’s ideas and language evolved over the course of four decades. Now that researchers have access to Erikson’s entire body of work, and five decades of research by others, a comprehensive, well-integrated understanding of the theory clarifies common misunderstandings and greatly enriches thinking about integrity and despair as the psychosocial theme that dominates later life. Near the end of his career, Erikson and colleagues used an empirical study as a basis for rearticulating, elaborating, and integrating three principles that are central to understanding his theory. ...