This report examines the extent to which California high school students fail to meet the high school course requirements for admission to California's four-year public universities. It investigates students' course-taking patterns and whether the courses they take meet the universities' entrance requirements. Because students from a variety of minority groups have been and continue to be underrepresented in California's colleges and universities, this study includes a subgroup analysis by ethnicity. The study documents patterns of high school course-taking associated with preparation for college and entry into two-year California community colleges and four-year California State University (CSU) and University of California (UC) institutions. The findings demonstrate a consistent pattern: students who complete college-preparatory courses in 9th grade begin a clear trajectory that continues throughout high school. Compared with students who do not take key college preparatory courses in 9th grade, students who do take these courses have a higher probability of meeting the complete set of CSU and UC course requirements. Students who fall off the college-preparatory track early in high school tend to move ever further from a complete college-preparatory program as they progress through high school. These patterns are examined by ethnicity and the overall performance of the school that a student attends. The following are appended are: (1) Summary of the A-G Subject Requirements; and (2) About the Dataset. (Contains 35 notes, 18 figures, 11 tables, and 1 box.) [This report was prepared for the Institute of Education Sciences (IES) by Regional Educational Laboratory West administered by WestEd.]