Erik Erikson was a German-born American psychoanalyst and developmental psychologist who is best known for his theory of psychological development. He is credited with coining the phrase 'identity crisis' and is considered one of the most influential psychologists of the 20th century. He is also known for his eight-stage theory of psychosocial development, which outlines the stages of human development from birth to death. His work has had a profound impact on the field of psychology and has been widely studied and applied in many different contexts.