The plural, "heroes," is the appropriate word here. One of the wonderful things about Rowling's books is the way Harry's triumphs are always dependent on his friends. Rowling's own story, her rise from scrabbling obscurity to prosperous fame, has often been said to parallel Harry's. "Goblet of Fire" makes clear that her sympathies also lie with Ron and Hermione. Among fans of the series, that studious, bushy-haired girl inspires the same sort of protective love that Willow does among viewers of "Buffy the Vampire Slayer." As always, Rowling pokes fun at Hermione's bookishness. (What similarly bookish character isn't kidded by its creator?) In "Goblet of Fire," Hermione also becomes the focus of a sympathetic satire (that may make the book's adult readers wince in recognition) of the self-righteous indignation adolescents indulge in when they discover the injustices of the world.

Harry and especially Ron have always regarded Hermione as a girl. Appropriate to a novel that finds the three of them at 14, that's suddenly become less of a liability. And Rowling rewards Hermione with an entrance at a winter ball that justifiably shuts her two pals up. (Lest you think the author is abandoning the core of the character, Hermione is right back at her books the next morning.)

Ron, the essence of the regular-guy sidekick and progeny of a large, perpetually down-at-heels wizard family, is undergoing adolescent throes of a different sort. He's at the age where he feels most keenly the privations of his family situation, where the shabbiness of his robes and used textbooks embarrasses him. Ron's uncharacteristically bitter exclamation to Harry and Hermione, "I hate being poor," cuts deeply. No doubt that's because Rowling has been there herself. In an interview with Newsweek, when asked if she was happy that she could now buy whatever she wants, she simply said the best thing about having money is "the absence of worry."

A new character, Rita Skeeter, a scandal-mongering reporter for the wizard newspaper the Daily Prophet, comes out of Rowling's experience in another way. Most likely, the caricature is Rowling's swipe at the tabloid reporters who dug up her Portuguese ex-husband and got him to make disparaging remarks about the author. On the other hand, if you live in England, a country with the most vicious tabloid press in the world, you don't need any personal experience to come up with a character like Skeeter.

Rowling's other regulars -- Hagrid, Dumbledore, Snape and the others -- have taken on the vitality of great popular characters. They seem more themselves than ever. And yet part of the deepening pleasure of the series is the way Rowling is making her young heroes aware of contingency, of the impurity of motives, of how good and evil are never as simple as they at first appear.

Ultimately, no great fantasy is ever an escape. When they are introduced into fantasy worlds, pain and loss can feel even keener. Think of moments like the one when Buffy sends Angel to hell just after he regains his soul; the scene in "Superman II" when Superman gives up his powers in order to love Lois as a man and then finds himself unable to protect her; the scene in "Tarzan of the Apes" when the ape mother substitutes for her dead baby chimp the human infant who will grow up to become Tarzan. By the time it reaches its climax, "Harry Potter and the Goblet of Fire" achieves that sort of excruciating and rapturous force.

By time time I finished it I was wrung out, exhausted and transported. Like all great fantasy sagas, the Harry Potter books have grown narratively, morally and psychologically more complex as the series progresses. There is a special pressure on a writer who midway through a series finds herself entrusted with the imagination of a huge number of readers. That Rowling has done nothing to break that faith seems a deed as brave and noble as any her hero has accomplished.

Maya Angelou reads from "The Heart of a Woman"