New knowledge about human development from neuroscience and the sciences of learning and development demonstrates that effective learning depends on secure attachments; affirming relationships; rich, hands-on learning experiences; and explicit integration of social, emotional, and academic skills. Given that emotions and relationships strongly influence learning--and that these are the byproducts of how students are treated at school, as well as at home and in their communities--a positive school climate is at the core of a successful educational experience. In this paper, the authors examine how schools can use effective, research-based practices to create settings in which students' healthy growth and development are central to the design of classrooms and the school as a whole. The authors describe key findings from the sciences of learning and development, the school conditions and practices that should derive from this science, and the policy strategies that could support these conditions and practices on a wide scale. In order to create schools that support healthy development for young people, our education system needs to: (1) Focus accountability, guidance, and investments on developmental supports; (2) Design schools to provide settings for healthy development; and (3) Enable educators to work effectively. [For the research brief, see ED606461. This document draws upon the following articles: "Implications for Practice of the Science of Learning and Development" (EJ1249443); "Malleability, plasticity, and individuality: How children learn and develop in context" (EJ1230868); and "Drivers of human development: How relationships and context shape learning and development" (EJ1241861).]