J.K. Rowling, author of the world-wide best-selling Harry Potter series, met some of her American fans tonight and provided some surprising revelations about the fictional characters who a generation of children have come to regard as close friends. In front of a full house of hardcore Potter fans at Carnegie Hall in New York, Rowling, sitting on the stage on a red velvet and carved wood throne, read from her seventh and final book, "Harry Potter and the Deathly Hallows," then took questions. One fan asked whether Albus Dumbledore, the head of the famed Hogwarts School of Wizardry and Witchcraft,...