Erik H. Erikson

Erik Erikson(1902-1994) is known for his theory on social development of human beings, and for coining the phrase 'identity crisis[?]'.

The theory describes eight stages through which a healthily developing human should pass from infancy to late adulthood. In each stage the person confronts, and hopefully masters, new challenges. Each stage builds on the succesful completion of earlier stages. The challenges of stages not successfully completed may be expected to reappear as problems in the future.