This paper identifies six core principles and recommends strategies that will foster high academic achievement, close the achievement gap, and promote civic and personal growth among all high-school-age youth in the high schools and communities. At the center of the framework is the Alliance's belief that the purpose of high school is to ensure that all high-school-age students are ready for college, careers, and active civic participation. It represents the collective knowledge of the National High School Alliance partners. It is designed to provide policymakers, practitioners, researchers, and the general public with a framework for guiding the complex process of transforming the traditional, comprehensive high school.