Erik Erikson first published his eight stage theory of human development in his 1950 book Childhood and Society. The chapter featuring the model was titled 'The Eight Ages of Man'. He expanded and refined his theory in later books and revisions, notably: Identity and the Life Cycle (1959); Insight and Responsibility (1964); The Life Cycle Completed: A Review (1982, revised 1996 by Joan Erikson); and Vital Involvement in Old Age (1989). Erikson's biography lists more books.