This chapter overviews what we know about effective programs and policy elements that promote healthy brain development for young children in different contexts--within family environments, in out-of-home early childhood care and education settings, and through interventions for children experiencing extreme stress. Each section describes successful programs, identifies elements of effectiveness, and discusses how the information applies to Wisconsin. This chapter closes with implications for Wisconsin policymakers on evidence-based and promising policies and programs, and effective implementation strategies. (author abstract)