This document summarizes the findings of the Committee on Integrating the Science of Early Childhood Development. The committee concluded that early experiences influence brain development and that nurturing relationships are important for healthy development. However, early intervention programs that work are rarely simple or inexpensive. The committee made recommendations for policy and practice, including giving greater attention to social-emotional development, recognizing the importance of early childhood educators, enhancing support for working families, and reducing fragmentation of policies and services to better support early childhood development.