One education reform that has the potential to leave its mark on education for many years is the P-16 initiative. The name refers to the range of "grades" included, beginning with preschool and running through the postsecondary undergraduate years. Though such efforts are most commonly called P-16, they are in some cases referred to as P-20 (or K-20) to demonstrate the importance of preparing a highly skilled work force in the years beyond undergraduate education. P-16 systems are intended primarily to smooth transitions between the different levels of education and into the work force. In this article, the authors provide a detailed overview of the reform's objectives, the mechanisms used to create P-16 systems, and the progress that specific states have made toward achieving the ideal of "seamlessness." (Contains 18 endnotes.)