This project consists of the implementation and evaluation of a developmentally based intervention program integrated into existing Head Start programs in order to promote the school readiness of socioeconomically disadvantaged children. Forty Head Start classrooms will be randomly assigned to the enriched intervention Head Start (Head Start REDI - Research-based Developmentally Informed) or to "usual practice" Head Start. Using a longitudinal study design, a sample of 320 children will be assessed annually over a four-year period (pre-test at age 3; post-test at age 4; follow-up assessments at age 5 and age 6, at the end of kindergarten and first-grade, respectively). The developmental trajectories and early elementary school adjustment of 160 children attending 20 Head Start-REDI classrooms will be compared to those of 160 children attending 20 "usual practice" Head Start classrooms. The enrichment intervention will utilize brief lessons, "hands on" extension activities, and specific teaching strategies linked empirically with the promotion of: 1) language development and emergent literacy skills, and 2) social-emotional competencies. Take-home materials will be provided to parents to enhance support for skill development at home and to foster parent-teacher involvement. Assessments of child outcomes will include multi-method, multi-informant measures of child social-emotional competencies, oral language skills, emergent literacy skills, cognitive abilities, and behavior problems. Teaching processes will be measured to assess program fidelity and relation to child outcomes. Analyses will assess: 1) the impact of intervention on child skill development and later school adjustment and achievement, 2) the relation between teaching practices (intervention fidelity and general teaching strategies) and child skill development and school adjustment, 3) the potential moderation of intervention effects by child characteristics, 4) the potential mediation of school adjustment by preschool gains in child language/literacy skills and social-emotional competencies, and 5) the use and impact of parent take-home materials. In addition, the proposed project will include activities designed to promote the sustainability and dissemination of the intervention.