The primary goal of this research project is to investigate the effectiveness of an integrated curriculum model intended to prepare children for successful school entry (RFA-HD-03-03). This curriculum model, Children's School Success (CSS), was developed through a planning grant project that involved investigators, research experts, and community partners. The CSS curriculum model consists of academic, social, and individualization components that are well integrated and have a solid-base of scientific evidence documenting their effectiveness. The aims of this research project are a) to train teachers to implement the CSS intervention model, provide ongoing support for implementation, and assess fidelity of treatment for the intervention model, b) assess and analyze the immediate effect of the CSS intervention model on the learning and development of four-year-old children at risk for school failure, c) assess the effects of the intervention model on children' s success in early elementary school years and d) determine the contextual characteristics of children, families, teachers, and organizations that affect fidelity of treatment and outcomes for children. The project will take place in 60 classrooms at five regional locations (CA, IN, KS, MD, WV) and involve approximately 600 children. These classrooms are located in Head Start, State Pre -K, and public school preschool programs. Children at risk for failure when entering the public schools are defined as four-year-old children living in poverty, children with identified disabilities, and children who are English Language Learners. A randomized group design will be employed in which teachers/classrooms are randomly assigned to conditions. Children in the experimental (i.e., receiving CSS Curriculum) and control (i.e. receiving typical curriculum in classroom) groups will be assessed with a battery of language, academic and social assessments at the beginning and end of the preschool year. Each spring, academic achievement and social assessments information, as well as school referral and placement information will be collected. To investigate the effects of institutional, personnel, and cultural variables on the implementation of the curriculum and effects for children, a cross-site case study analysis will be conducted. In addition, a comparison of costs of the CSS curriculum implementation relative to the standard curriculum in the preschool programs will be conducted.