A growing number of states are taking steps to transform three largely disconnected levels of public education--preschool, K-12, and postsecondary--into a more coherent, integrated system called P-16. P-16 is based on the concept of a seamless continuum of public education stretching from preschool to grade 16, culminating in a baccalaureate degree. Among the major goals of a P-16 system are expanding access to early learning for children ages 3 to 5; smoothing student transitions from one level of learning to the next; closing the achievement gap between white and minority students; upgrading teacher education; and improving college readiness and college success. Legislators are uniquely positioned to provide vision and leadership for P-16 initiatives in their states. They can play a crucial role in addressing shortcomings of the current system; exploring strategies for closing gaps and overcoming institutional resistance; and building consensus for change. This primer is a practical guide to a P-16 educational system. It contains a basic orientation to P-16 education, an overview of the varying definitions of P-16, and specific policy questions for legislators to consider. Appendices include a glossary of terms, a list of selected readings, and links to a variety of resources and materials on P-16. (RT)