This op-ed by Secretary Margaret Spellings appeared in the Riverside Press Enterprise (CA), New Bedford Standard Times (CT), Saint Paul Pioneer Press (MN), Duluth News Tribune (MN), Augusta Chronicle (GA), and Spokane Spokesman Review (WA).

The recent release of the new Harry Potter book reminds us of the power of imagination, engaging the hearts and minds of children in our own country and encouraging them to read. The newest book in the Potter series about a bespectacled British wizard is a hefty 672 pages long—a fact that has not deterred young readers from devouring them worldwide. It's wonderful to see such enthusiasm about literature.

We also had some heartening news recently about how well children are reading. According to the new National Assessment of Educational Progress long-term trend assessment, also appropriately known as "America's Report Card," 9-year-olds scored better in reading and mathematics than they ever had in the 30-year history of the test. All student achievement—for whites, blacks and Hispanics—increased dramatically. Of equal importance, that pernicious, decades-old achievement gap that separates minorities and whites shrunk to its smallest size in history for our youngest learners.

And more than half of the historically unprecedented gains in reading seen over this 32-year period came in the past five years for our youngest learners. The results are a tribute to students, teachers, parents, principals, school administrators, and state and national policymakers everywhere.

Another interesting finding: Both 9- and 13-year-olds are reading more than they used to—more than 20 pages a day—which I think is safe to say has something to do with the NAEP reading gains. To put it simply: When you work harder, you get better results.

Compare these statistics to the recent National Endowment of the Arts study that found that young adults (ages 18-24) suffered from the steepest decline in literary reading of all age groups surveyed over the past 20 years. Having books such as "Harry Potter" help students learn to love reading at an early age is crucial.

What could have happened at school recently to cause such a positive spike in results? The answer is years of state and national education reform, most recently and most notably in the form of No Child Left Behind. Never before has the United States—or any nation that is as culturally and economically diverse—sought to provide all of its citizens with a quality education, and set a deadline to do it. The NAEP results prove the fundamental belief underlying No Child Left Behind: that every child can learn. Thanks to the hard work of parents, teachers, principals, and state, local and national policy-makers, we can see that all children are capable of tremendous improvement when our schools believe in them and hold them to high standards.

But we still have work to do. The results show that as children go through the educational system, their learning gains start to slow down in their early teens and are flat by the time they reach high school. The report card for 13-year olds is mixed, with increased scores among all ethnic groups since the '70s in reading and math, but no significant shrinking of the achievement gap. And the news for 17-year-olds is dimmer: Scores are essentially flat in both reading and math over the past three decades.

Overall, I found hope in the latest Report Card, but I know we can do better. We are moving in the right direction, but the challenge before us is to stay the course. We can clearly see that No Child Left Behind is working with its focus on children in the earlier grades, but we have to continue to be smart about the way the law is executed on the ground. That's why the Department of Education has announced a series of measures to help schools better implement the law for the benefit of all students. We want to ensure that this law is truly workable for the educators doing the tough work and those children ultimately benefit by having a solid educational foundation.

The next question is, Where do we go from here? The results should guide policy decisions. Given the results of the 17-year olds in the sample, it's obvious that we must get serious at the national level about high school reform. The American high school must do a better job at graduating all its students and preparing them for the road ahead—be it the workforce or higher education. We know our children enjoy reading, as any young Harry Potter fan will tell you. And we know they can improve, as the NAEP test scores tell us. Now it's up to adults to create a world where all children receive the quality education they so deserve.

Margaret Spellings is U.S. Secretary of Education.