A Screenwriter’s Hogwarts Decade

The three central characters — Harry (Daniel Radcliffe), Hermione (Emma Watson) and Ron (Rupert Grint) — have grown up on screen, enduring the twin horrors of Voldemort and adolescence before our very eyes. The stories have become progressively darker and more complicated. And Mr. Kloves has immersed himself so deeply in the world of Harry Potter that by the time J. K. Rowling’s seventh and final volume, “Harry Potter and the Deathly Hallows,” came out in 2007, he said, he knew the characters almost as thoroughly as she did herself.

Adapting the stories for film has been a delicate process all along, as faithfulness to books adored by millions has always had to be balanced with the conventions (and length) of Hollywood blockbusters. (Mr. Kloves is the screenwriter for all but one of the movies, “Harry Potter and the Order of the Phoenix.”) But “Deathly Hallows” was perhaps the most difficult of all. More than 700 pages long and crammed with quick-moving plot developments leading to an apocalyptic finale, the book ultimately proved too dense to make into a single film. So it has been split into two.

Part 1, to be released on Friday, covers the first half of the novel, a kind of prolonged road trip in which Harry, Ron and Hermione become nomads in hiding, sorting out their feelings for one another while eluding capture and searching for magical objects that must be destroyed before Voldemort (Ralph Fiennes) can die. Part 2, which builds to a final battle between good and evil inside the Hogwarts School of Witchcraft and Wizardry, is scheduled for release in the summer of 2011.

“When the idea was initially mooted, I was, to put it mildly, uncertain,” said David Heyman, one of the key producers, speaking of the decision to make two movies from one book. “But as Steve began to break the book down, it became clear that there was no way to tell this story in one film and to have the film make sense and do the book any justice.” (And, of course, the decision allows Warner Brothers to spin out the franchise for one last probable box-office bonanza.) Though expectations for the finale are even higher than usual, the filmmakers say their approach has essentially stayed the same throughout the series.

“I took my cues from Jo,” Mr. Kloves said, speaking of Ms. Rowling. “The first day I met her, she said: ‘I know the movies can’t be the books. All that I ask is that you be true to the characters.’ And I believe I’ve fulfilled that request.”

Owl-eyed Harry Potter scholars will spot small divergences from the book even at the outset, when Harry bids farewell to his hateful relatives, the Dursleys (a moment of sympathy from Dudley, Harry’s cousin, was cut from the film), and when Hermione, heartbreakingly, protects her parents by casting a spell that erases herself from their memories. (The scene is merely alluded to in the book.) Some big things have been left out — Harry’s birthday party, for instance — and some small things added, like a scene in which Hermione and Harry, bereft and depressed in the wilderness after Ron walks out in a huff, spontaneously dance together as music plays on their radio. (Mr. Heyman said the scene had been inserted to show the two friends’ deep affection for each other and to make the point that even in the midst of everything, they are still kids.) But the story, as ever, remains faithful to Ms. Rowling’s narrative.

Writing the script for “Deathly Hallows” was in some ways easier than writing the earlier scripts, Mr. Kloves said, because it was the first time he knew how Ms. Rowling’s epic would end. For the previous movies he had to use his best judgment about what was yet to come.

Ms. Rowling always vetted his scripts, however, stepping in when she could see Mr. Kloves veering off course. Early on, for instance, she redirected his approach to Dobby, the downtrodden house-elf. “I had elected to slightly de-emphasize him, and she said, ‘Dobby’s going to be important, and so you want to revisit the scene,’ ” Mr. Kloves said. (Dobby plays a pivotal role in the new movie.)

After a while, Mr. Kloves said, “I had a remarkable ability to anticipate events, because I swam in the narrative for 10 years.” For example, he said, he always suspected that behind the oily nastiness of Severus Snape (Alan Rickman) lurked a man of deep bravery with his own lonely integrity.

“You can never decipher where Jo will take the plot, because she is completely original,” Mr. Kloves said. “But there was no question in my mind that Snape was going to be heroic, and I wrote him that way from the start.”

Similarly, he said, he always suspected that Dumbledore was gay, though this was never stated explicitly in any of the books, and though Ms. Rowling had to point it out to him in the margin of one of his earlier scripts, lest he put in a confusing line implying that Dumbledore was reminiscing about a girl he once knew. (Ms. Rowling publicly announced that Dumbledore was gay at an event in Carnegie Hall in 2007.)

“When you live within a narrative the way I have and you start to feel the DNA of the book, you can tell,” Mr. Kloves said. “There was something about the way she wrote about him. There was a freedom and a quality to his humor that made him someone who was slightly outside, and who was comfortable being outside normal conventions.”

But he admitted to a spectacular misjudgment: He thought that Hermoine would be killed.

“If you read the books, you can argue that Jo’s setting it up,” he said. A dinner party attended by Ms. Rowling — during which he and some other guests began a parlor game of Harry Potter predictions — convinced him further.

“I said, ‘I think Hermione’s going to die,’ and at that point, Jo said, ‘I think we should stop the game now.’ When I read the book, I thought, ‘Bloody hell — how could you do that to me?’ ”

Each movie in the series has felt a little darker, a little more frightening, with stakes that are a little higher. The new one opens with a horrific scene in which a Hogwarts professor is suspended upside down in the air, grotesquely spinning around as tears trickle from her eyes, while Voldemort (Ralph Fiennes) and his evil Death Eater minions plot how to kill Harry. (The scene does not end happily for her. Never has an invitation to dinner seemed quite as scary as the one Voldemort issues to his malevolent pet snake, Nagini.)

Ms. Rowling has always said the series would end with “Deathly Hallows.” But years of back-and-forth correspondence with her, Mr. Kloves said, have revealed that the material in the books is just “the barest surface of what she knows about that world.”

“If you can get her to talk about it, it’s so remarkable what she knows,” he said. “I once e-mailed her and asked her what were the 12 uses of dragon’s blood” — information that is taught to Hogwarts students — “and she wrote back in 30 seconds what they all were. If I ask about Ron’s uncle, I get back five pages about Ron’s uncle, who never appears in the books.”

“I can’t tell you how great this stuff is,” he added. “It’s almost a crime for it not to be published.”