The authors, pioneers in detracking and in shrinking achievement gaps, pose a question: Is it possible to have all students in a large high school successfully complete a challenging curriculum that gives them practice in the habits and skills necessary for success in college? The answer, they say, "is a resounding yes." This article describes how South Side High School in Rockville Centre, New York, gradually reworked its curriculum so that all 9th and 10th graders take rigorous classes that prepare them for courses in the International Baccalaureate curriculum and almost all 11th and 12th graders take an IB math and an IB English course. Focusing on the course IB English Language and Literature, they demonstrate how teachers can differentiate instruction in a way that maintains the complexity of academic tasks while varying the tasks' difficulty level--so students of all levels and backgrounds can master college-level work.