The school readiness goal of the America 2000 educational reform program admits that not all children start school ready to learn, but implies that with proper and adequate interventions, all children can start with the requisite cognitive and social adaptive skills that will enable them to learn. This paper discusses and analyzes critical skills related to the preparation and support of poor urban children in preschool and early school years. It is suggested that readiness does not reside in children as a fixed attribute, but is rather the result of the dynamic interaction between the child and the learning environment, in which each child's potential to succeed is mediated by significant adults and the supportive nature of the social and learning contexts in which children perform. The differences in support and environment faced by poor urban children are discussed, and the ways in which readiness is determined are reviewed. An ecological model of school readiness is proposed that suggests a dynamic process of reciprocal influence of several factors that influence children's school readiness. The model includes the six components: (1) individual potential; (2) the larger distal social context; (3) proximal social contexts; (4) developmental pathways; (5) readiness indicators; and (6) school progress and growth. One figure outlines the model. (Contains 23 references.) (SLD)