For two decades, the state role in educating children before kindergarten has been growing, and it is accelerating. Enrollment in state-funded preschool today far exceeds that in federal Head Start, and states are the dominant provider at age 4, serving about half of all four-year-olds who attend any preschool program. New universal preschool initiatives in states around the country are poised to generate an unprecedented boom in state-funded preschool over the next decade. Children's "hard" and "soft" skills -- language, literacy, math, science, and social and emotional development -- improve in the short run. In the long term, they see increased achievement, better classroom behavior, less grade retention and special education, reduced delinquency and crime, and increased educational attainment. To ensure that programs deliver these outcomes, state policymakers must attend to access, quality, funding, and supports for continuous improvement. Preschool for all requires legislating preschool as an entitlement and ensuring that adequate funding follows enrollment. Great opportunities and challenges lie ahead for state boards that seek to improve children's early education and long-term educational success. While the opportunities and challenges vary by state, every state will need to address enrollment, quality standards, funding adequacy, evaluation and continuous improvement, state capacity, and alignment with K-12.