This report provides three in-depth case studies of states that are working to build P-3 systems. These case studies address a central question: How can states support P-3 system building at both state and local levels? In addressing this question, the case studies provide significant detail about each state's P-3 policies and approaches to local support, yielding a range of examples intended to inform the thinking of state early childhood administrators as they design policies and programs to meet the needs of their specific state contexts. (author abstracts)