Of all the magical powers wielded by Harry Potter, perhaps none has cast a stronger spell than his supposed ability to transform the reading habits of young people. In what has become near mythology about the wildly popular series by J. K. Rowling, many parents, teachers, librarians and booksellers have credited it with inspiring a generation of kids to read for pleasure in a world dominated by instant messaging and music downloads.

And so it has, for many children. But in keeping with the intricately plotted novels themselves, the truth about Harry Potter and reading is not quite so straightforward a success story. Indeed, as the series draws to a much-lamented close, U.S. statistics show that the percentage of youngsters who read for fun continues to drop significantly as children get older, at almost exactly the same rate as before Harry Potter came along.

There is no doubt that the books have been a publishing sensation. In the 10 years since the first one, "Harry Potter and the Sorcerer's Stone," was published, the series has sold 325 million copies worldwide, with 121.5 million in print in the United States alone. Before Harry Potter, it was virtually unheard of for kids to queue up for a mere book. Children who had previously read short chapter books were suddenly plowing through more than 700 pages in a matter of days. Scholastic, the series's United States publisher, plans a record-setting print run of 12 million copies for "Harry Potter and the Deathly Hallows," the eagerly awaited seventh and final installment due out at 12:01 a.m. on July 21.

But some researchers and educators say that the series, in the end, has not permanently tempted children to put down their Game Boys and curl up with a book instead. Some kids have found themselves daunted by the growing size of the books ("Sorcerer's Stone" was 309 pages; "Deathly Hallows," will be 784). Others say that Harry Potter does not have as much resonance as titles that more realistically reflect their daily lives. "The Harry Potter craze was a very positive thing for kids," said Dana Gioia, chairman of the National Endowment for the Arts, who has reviewed statistics from U.S. and private sources that consistently show that children read less as they age. "It got millions of kids to read a long and reasonably complex series of books. The trouble is that one Harry Potter novel every few years is not enough to reverse the decline in reading."