The rapidly growing field of infant research and clinical experience has brought into renewed focus an emphasis on the ego and its myriad roles in human development.

Working with infants and their families, prenatally as well as after birth, Dr. Greenspan has evolved a systematic study of the ego in the first four years of life. Studying both high-risk and adaptive families, he has defined six stages of the evolving ego: Homeostasis (self-regulation and interest in the world, 0-3 months); Attachment (2-7 months); Somatopsychological Differentiation (purposeful communication, 3-10 months); Stage of Behavioral Organization, Initiative, and Internalization (9-18 months); A Complex Sense of Self Rep-resentation