How well are our nation's high schools preparing students for college and career? Recent analyses by ACT show low rates of college and career readiness among United States high school graduates. Data from postsecondary institutions reveal high remediation rates and low second-year retention rates among first-year college students. Employers lament the difficulty of finding entry-level employees with the necessary skills for success on the job. All of these suggest disparities between students' high school preparation and the level of readiness required for postsecondary education, training, and the workplace. But the criteria for evaluating school effectiveness at preparing students are numerous, varied, sometimes conflicting, and frequently based on opinion. And too often these criteria overlook the crucial factor of what is actually going on in the classroom. Preparation for college and career occurs substantially in the classroom. What is taught and learned in the courses students take--especially the core courses in English, mathematics, and science--contributes substantially to what students are able to do once they leave high school with diploma in hand. What is needed is evidence that not only enables us to see what the core courses in our schools currently contribute toward preparing students for college and career, but also gives us an idea of how much improvement is needed within each course if we are to help all high school graduates become ready for college and career. This report examines the degree to which core courses, as they are currently taught in a nationally representative sample of U.S. high schools, are effective in preparing our nation's high school graduates to enter some form of postsecondary education (a two-year, four-year, trade, or technical school) without remediation or to enter workforce training programs ready to learn job-specific skills. In short, this study establishes an empirical baseline for the value added to college and career readiness by core courses in high schools across the nation. Sampling Process and Study Methodology are appended. (Contains 33 figures, 8 tables and 5 footnotes.)