Responsible elementary schools strive to ensure that all pupils know more today than they knew yesterday thereby better preparing the youngsters for tomorrow's lessons. However essential that aim, achieving the goal faces serious challenges due to what confronts quality classroom teachers daily: "It's not the budget crisis or standardized testing...It's the enormous variation in the academic level of students coming into any given classroom..." Our current educational system's rigid graded format, i.e., first grade, second grade, is unable to accommodate this extraordinary pupil diversity. By habit rather than wise thinking, schools assign 25-30 children to classrooms and a teacher's curriculum on the basis of age with no consideration for skills, a flawed approach called "lumping." Doing so, even superior teachers are forced by time constraints to ignore many youngsters' educational strengths and weaknesses thereby increasing the likelihood those schoolkids will suffer discordant "curriculum mismatches." The book provides teachers and principals an effective alternative to the antiquated "one-size-fits-all" approach that ignores both advanced and struggling pupils, leaving many school children without essential everyday skills. The promising option offers all youngsters-low achievers, high achievers, and those in between-the opportunity to advance through the curriculum as far and as fast as their acquired skills allow.