So far, we have seen just how competent newborn infants are, and how poised and ready they are to relate to those who care for them. As they get established in these early relationships with those who, hopefully, will remain with them until they grow up, babies begin to show signs of what we will call ‘getting organized’. Those who spend time around young babies will see during these months that they change in very noticeable ways, at particular times. On the outside, the babies will move from eating only milk, breast or bottle, to solid food and, by the end of the first year, will probably be interested in a wide variety of ordinary foods and begin to show preferences for what they like or dislike; they will almost certainly be on the move, crawling if not already walking; they will probably have established a reliable sleep pattern where they sleep for some time during the day and have a long uninterrupted 10-12-hour sleep at night time; they possibly will also have uttered sounds remarkably similar to recognizable words and intended for communication about something. Increasingly, there will be a sense that the baby is gradually becoming a person. Internally, changes are also progressing apace, partly as a consequence of an inbuilt developmental programme with which we are all born and partly in response to the experiences babies have with those who care for them. In this chapter we are going to chart the changes that take place during the first year of life that we see as evidence of this ‘organization’ that is central to the internal emotional and social development of the baby.