The National Research Council of the National Academies has been charged by Congress with ensuring that the best scientific understanding illuminates key challenges facing the nation and informs policy choices. Few challenges are more crucial than fostering the healthy development of America's children and their capacity to learn and achieve success in school. Child development, learning, and education have been high priorities of the National Academies in the past two decades. An explosion— and convergence—of knowledge from the cognitive, behavioral, social, and neurosciences has brought into much sharper focus the picture of how human development unfolds and the factors that determine whether children are equipped to learn and to flourish. With the nation's attention focused on the need to improve children's educational achievement, science has much to offer in making gains toward that end.

Compelling new scientific evidence reveals that a child's earliest experiences have a major role in shaping the likelihood of getting off to a good start in life and school, for these are the years when the essential structures for growth and learning are put in place. These findings have important implications for the content of child care and early education programs and highlight the public interest in assuring the quality of those programs.

Similarly, decades of research on the science of learning has shown that deep understanding requires both a rich foundation of factual knowledge and command of the subject 's conceptual frameworks—whether it be chess, mathematics, or jet engine mechanics. This research has impor-