Erikson's Stages of Development is a theory proposed by Erik Erikson that outlines eight key stages individuals go through from infancy to adulthood. Each stage presents a specific conflict or challenge that must be resolved for healthy psychological development. Successful resolution leads to a positive outcome, while failure can result in difficulties later in life. The stages include Trust vs. Mistrust in infancy, Autonomy vs. Shame and Doubt in early childhood, and Identity vs. Role Confusion during adolescence, among others. Each stage builds on the previous one, emphasizing the importance of social relationships and personal growth throughout the lifespan.