GEORGE STEPHANOPOULOS (ABC NEWS)(OC): There is big news today in the world of books. The best-selling author of our time by a mile is back at her keyboard. JK Rowling, the imagination behind Harry Potter, is writing her first novel since she completed the Potter series five years ago. And just as her boy wizard has grown up and moved on, so has Rowling. As ABC's Dan Harris reports, her new book is aimed at adults.
DAN HARRIS (ABC NEWS)(VO): JK Rowling's Harry Potter books, about a boy wizard, cast a powerful spell. Not only getting millions of kids interested in reading...
CHILD (FEMALE): I picked it up. And it was so good, I finished it in about three days.
DAN HARRIS (ABC NEWS)(VO): But also becoming the most successful publishing franchise ever, selling 450 million copies.
DAN HARRIS (ABC NEWS)(VO): The movies were the largest-grossing in history, taking in $7.7 billion.
DAN HARRIS (ABC NEWS)(OC): But her new book for grown-ups, that's pretty much a blank page. We don't know what it's called, what it's about or when it's coming out.
DAN HARRIS (ABC NEWS)(VO): All we do know is what Rowling said in a statement. My next book will be very different to the Harry Potter series. While the Potter books made this single mom on welfare wealthier than the Queen of England, can she really make the switch to grown-up literature? Rowling herself seemed to have some doubts when she finished the last of the seven Potter books in 2007.
JK ROWLING (AUTHOR): I do look forward to a post-Harry era. But at the same time, I dread leaving Harry.
DAN HARRIS (ABC NEWS)(VO): It is true that children's authors rarely succeed in adult literature.
JIM MILLIOT (PUBLISHERS WEEKLY): But JK Rowling isn't any other author. I mean she's got such a brand, such a franchise. It's a guaranteed, you know, biggest book of the year.
DAN HARRIS (ABC NEWS)(VO): As he points out, millions of adults read the Potter books, sometimes in secret, and so many of those children who grew up on her books are now grown-ups themselves. In fact, the very first book begins with Harry Potter's 11th birthday.
DAN HARRIS (ABC NEWS)(VO): He would be 26 today. Dan Harris, ABC News, New York.
GEORGE STEPHANOPOULOS (ABC NEWS)(OC) Boy, people are going to gobble that up.