The No Child Left Behind (NCLB) Act of 2001 created the Early Reading First (ERF) program to enhance teacher practices, instructional content, and classroom environments in preschools and to help ensure that young children start school with the skills needed for academic success. This report to Congress describes the impacts of the Early Reading First program on the language and literacy skills of children and on the instructional content and practices in preschool classrooms. The main findings of the national evaluation of ERF show that the program had positive, statistically significant impacts on several classroom and teacher outcomes and on one of four child outcomes measured. The program had no effect on children's phonological awareness or oral language. This report contains an executive summary and eight chapters: (1) Introduction and Study Background; (2) Study Design; (3) Characteristics of Participating Children and Families; (4) Characteristics of Programs Receiving ERF Funding; (5) Professional Development, Instructional Practices, and Classroom Environments in ERF Preschools; (6) Impacts on Teachers and Classroom Practices; (7) Impact Findings: ERF Impacts on Children's Language and Literacy Skills and Social-Emotional Outcomes; and (8) Analysis of Mediators of ERF's Impacts on Classroom Instructional Practice and Children's Language and Literacy Skills. Appendices include: (A) Impact Analysis Methods and Sensitivity of Results; (B) Data-Collection Methods; (C) Assessment and Observation Measures Used for ERF Data Collection; (D) Supplementary Tables on the Impacts of ERF on Teachers and Classroom Environments; (E) ERF Impacts on Teacher and Classroom Outcomes; Subgroups Analyses; (F) ERF Impacts on Child Outcomes; Subgroups Analyses; and (G) Supplemental Descriptive Tables for Teacher Outcomes and Classroom Practice. (Contains 63 tables, 12 figures, and 5 exhibits.) [This report was produced by the National Center for Education Evaluation and RegionalAssistance, Institute of Education Sciences.]