When we talk about child development we are not talking about targets or milestones or learning areas or a curriculum. We are talking about what thinkers and researchers have found out about how children, in the social world in which we all live, become able to make sense of the world, to express their thoughts and ideas and feelings and to solve problems they encounter as they themselves raise and answer questions. We take the view of the child as competent being, worthy of respect, and learning, primarily, through language and communication. In this chapter we turn our attention to understanding what is thought about how children learn and develop. An understanding of this is essential to planning in the sense that we have to have some theoretical underpinning to analyse what we see and hear, and you now know that it is only by recognising what children already know and can do and are interested in that we can plan for their learning and development.