E. D. Hirsch, author of The Knowledge Deficit, draws on recent findings in neuroscience and data from France to provide new evidence for the argument that a carefully planned, knowledge-based elementary curriculum is essential to providing the foundations for children's life success and ensuring equal opportunity for students of all backgrounds. In the absence of a clear, common curriculum, Hirsch contends that tests are reduced to measuring skills rather than content, and that students from disadvantaged backgrounds cannot develop the knowledge base to support high achievement. Hirsch advocates for updated policies based on a set of ideas that are consistent with current cognitive science, developmental psychology, and social science. The book focuses on six persistent problems of recent US education: the over-testing of students; the scapegoating of teachers; the fadeout of preschool gains; the narrowing of the curriculum; the continued achievement gap between demographic groups; and the reliance on standards that are not linked to a rigorous curriculum. Why Knowledge Matters introduces a new generation of American educators to Hirsch's astute and passionate analysis.