U.S. high school students' lack of preparedness has serious implications for the economy and prosperity. For most of the nation's history, manufacturing workers with modest formal education could earn decent wages. For roughly 60 percent of the jobs in today's labor market, at least some postsecondary education is needed, and that percentage is expected to increase in the years ahead. The jobs of the 21st century require more sophisticated skills and knowledge. Businesses are looking for employees who can write and communicate clearly, analyze information, conduct research, and solve complex problems. Employers say the high school graduates they hire need the same skills and knowledge that colleges and universities assert enrolling students should have. Consequently, all students--those attending a four-year college, those planning to earn a two-year degree or get some postsecondary training, and those seeking to enter the job market right away--need to have comparable preparation in high school. To ensure that all high school graduates are prepared for postsecondary education and work, this action agenda indicates that governors and business and education leaders must develop a comprehensive plan for their states to: (1) Restore value to the high school diploma by revising academic standards, upgrading curricula and coursework, and developing assessments that align with the expectations of college and the workplace; (2) Redesign the American high school to provide all students with the higher-level knowledge and skills, educational options, and support they must have to succeed; (3) Give high school students the excellent teachers and principals they need by ensuring teachers and principals have the necessary knowledge and skills and by offering incentives to attract and retain the best and brightest to the neediest schools and subjects; (4) Hold high schools and colleges accountable for student success by setting meaningful benchmarks, intervening in low-performing schools and demanding increased accountability of postsecondary institutions; and (5) Streamline educational governance so that the K-12 and postsecondary systems work more closely together. (Contains 24 endnotes.) [This Summit was sponsored in partnership with the Hunt Institute.]