Calls over the last decade for national educational goals, high academic standards, and improved student performance represent the first sustained challenge to the dominant philosophy of schooling. Chapter 1, "The Professionalization of Curriculum Planning," traces the transformation of American education by elites professionalizing curricula and promoting public high schools. Chapter 2, "Vocationalizing the High School? Curriculum Expansion During the Progressive Era," explores the growing role of vocational education from 1900-1930. Chapter 3, "The Transformation of the High School During the Depression and War," documents a transformation in the nature and function of schools during the depression. Chapter 4, "The Triumph of Curricular Differentiation, 1950-1964," traces the continuing vitality of Progressive Era assumptions about the importance of a differentiated curriculum. Chapter 5, "The Triumph of Curricular Differentiation, 1964-1975," reveals the continuity in the assumptions guiding curricula during a tumultuous era. Chapter 6, "The Restoration of the Academic Ideal? Upheaval and Reform, 1975-1995," explores the first significant challenge to the differentiated curriculum. Chapter 7, "Implications for Policy and Practice," summarizes the failures of the differentiated high school curriculum and advocates several reforms. (Includes appendices A-E providing summary data regarding enrollment and subject areas for the United States, Grand Rapids (MI), Detroit (MI), the state of Michigan, and selected states and cities. Contains 300+ references and a 9-page index.) (TEJ)