This paper makes a fundamentally simple line of empirically supported argumentation. The increasing demands for high level student learning can best be achieved by the use of the substantive research evidence of the past decade demonstrating that developmentally oriented instruction facilitates academic, behavioral, and social performance. Most educators, however, have not been prepared to apply knowledge of child and adolescent development and learning and are thus not sufficiently able to provide developmentally oriented instruction. If children, communities, and the country, are to meet their potentials, then teachers need opportunities to learn, practice, and assess their abilities to provide developmentally oriented instruction. Recent research in the fields of education and psychology clearly demonstrates the relevance and importance of addressing the full range of student development in seeking positive school outcomes for students. The country can and should build state of the art schools and debate and design strong, meaningful academic standards and robust and diversified assessment systems to help determine improvement. All of this, however, requires a clear and deep understanding of the ways in which children grow, develop, and learn. This paper develops the case that a deep consideration of this essential knowledge base is vital to the performance of educators, and, more importantly, children, in classrooms. Without such knowledge, and the capacity of educators to apply it in the service of student learning, the noblest intentions, the finest standards, and the most reliable and valid assessments cannot succeed. Toward these ends, this paper (1) provides a framework for knowledge about child and adolescent development and learning that teachers can draw upon for quality instruction and (2) concludes with a set of recommendations for how pre-service teacher education can better prepare teachers to know and effectively apply this knowledge. [For the brief report, see ED550409.]