Erik Erikson was a German-American psychologist best known for his theory of psychosocial development. He proposed that people go through eight stages of development from infancy to old age, each characterized by a specific conflict that must be resolved. For example, during the first stage, infants face the challenge of trust versus mistrust, which sets the foundation for their future relationships. Erikson's work emphasized the importance of social and cultural influences on personality development. His ideas have had a lasting impact on psychology, education, and even parenting, helping us understand how our experiences shape who we become throughout our lives.