TO FIRST EDITION<br >There is a zest and vitality in human infancy that shows itself at<br >every turn. The infant looks with absorption， drinks in his environ-<br >ment well before he "knows how" to do anything about taking hold<br >of it. He scouts his world for every sign of what is novel and monitors<br >not only what goes on right before him but what is happening at the<br >edges of his world. At the start， in the opening weeks of life， the baby<br >is either alert， "turned on，" and in a mood to explore， or he is<br >"turned off" in the total way that young infants have of turning off.<br >Gradually， alertness spreads over longer periods and the infant be-<br >gins on new tasks--social life， manipulation of things， and the grad-<br >ual lacing together of the world of the eyes with the world of the<br >hands. A career of self-projected travel begins early--perhaps when<br >the baby can turn from his back to his tummy--and the realm over<br >which control extends expands as no empire ever has.<br > There are memorable landmarks. There is the first time the child<br >sustains his look into his mother s eyes and begins on a career of<br >social exchange of such complexity that no grammar has yet been<br >devised to explicate it. There is the first smile， earlier than the books<br >say， and a genuine expression of pleasure， in spite of early detractors<br >who suspected gas pains. There is the first time that the infant is able<br >to go on looking at the world around him while still feeding at breast<br >or bottle--probably the opening achievement of the art of doing two<br >things at once， which will burgeon later on. There is the first visually<br >guided reach for an object， hand wide spread， attention long sus-<br >tained， and a final capture with object delivered for inspection to the<br >mouth--the mouth， that lighthouse in the midline， the all-purpose<br >sense organ. And on it goes.<br > For those of us who study the growth of infant competence， the<br >mysteries are no less deep than for any other observer. We are only<br >beginning to appreciate how subtle the processes of growth are--<br >