This document summarizes Erik Erikson's psychosocial theory of development. It describes the eight stages of development from infancy to late adulthood, including the key conflict or strength developed at each stage. For example, the first stage of Trust vs. Mistrust occurs in infancy, when babies must learn to trust their parents' care and affection or may develop distrust. The document also provides overviews of Erikson's philosophy and the history and key concepts of his psychosocial theory.