In considering the challenges of basic skills education, Shulman returns to the advice of one of his mentors, Benjamin Bloom. The reason students fail, according to Bloom, is that they need more time to succeed, and time is what educators fail to give them. According to Bloom, nearly anybody can learn nearly anything given enough time. The fundamental error of educators is treating as a constant and permit achievement to vary. Bloom argued that achievement should be the constant and time, the variable. Based on this theory, learning should result in a kind of "J curve" in which most students end up clustered at the successful end of the continuum. Learning for mastery was Bloom's attempt to take this premise and work with educators across the country to design programs of instruction where the quality of instruction was modified, adapted and redesigned to insure that students experienced enough success to persist in their efforts. The author recognizes that time cannot be increased without limit for all students and all subjects, and that time alone cannot succeed without also improving the quality of instruction and student persistence. He does suggest that the most powerful approaches to learning, especially to the learning of students who have not been well served by the educational system, means being willing to think differently about the relationship between time and achievement. And, concludes Shulman, once the shackles of time are broken, it becomes possible to imagine ways to improve teaching, learning, student motivation and course design that can make a real difference.