This policy paper focuses on what emerging research tells policymakers about why it is so important to intervene to help young children at risk for poor social, emotional, and behavioral development, and what kinds of research-based interventions seem most effective. The paper addresses the relationship between early academic learning and emotional development, the prevalence of emotional problems in preschool-aged children and young children who are exposed to multiple family and environmental risk factors, and the role of teachers and child care providers in reducing or exacerbating problems. Also explored is the emerging but still limited research on the efficacy of preventive and early interventions explicitly targeted to address the social, emotional, and behavioral difficulties of young children, particularly in the context of early care and education settings. The paper concludes with recommendations for policymakers and researchers. (Contains 78 endnotes.) (KB)