Producer David Heyman is another who stumbled upon Harry Potter without quite realizing how it would transform his life. The manuscript sat on his low-priority shelf until one of his assistants took it home for the weekend, and came in raving about it Monday.

His smartest move was to form a tight alliance with Rowling. It's a widespread misconception that Rowling has all kinds of contractual rights of approval over the Potter movies. In fact, she has none, but Heyman has always gone out of his way to ensure that her voice is heard powerfully throughout the process of adaptation.

"I'm a big believer in authorial influence," he says. "Jo is an invaluable resource, and she's generous to a fault in giving us information. The books are just the surface of what's there; she has notebooks upon notebooks about this world, and any question you have, she already knows the answer. She's present when we need her, but never interfering. "

The determination of Rowling and Heyman to see the movies made in the U.K. with British actors also has made the Hollywood studios more open to approaching other British-based material without relocating it to New Jersey or insisting on American stars.

"If truth be told, the books are the star, and that has afforded us opportunities to do what we want with casting," Heyman says. "Why should we cast an American playing a Brit when we have so many great British actors, when we don't need the American star power?"

Heyman initially approached Brit uberscribe Richard Curtis, who would work only with Brit helmers Mike Newell or Alan Parker. Newell wasn't available, and Parker managed to talk himself out of the job. Now, of course, the wheel has turned full circle, with Newell directing the fourth installment, "Harry Potter and the Goblet of Fire."

"These films have helped to build the British visual effects business," Heyman says. "On the first film, the work was evenly divided between Britain and America, but as the series has developed, our trust in the British houses has increased. The quality of companies such as CFX, MPC, Cinesite and Double Negative is on a par with anywhere else in the world.

"Alas, they've also become as expensive," he adds.

"I had a first-look deal at Warner, but the nature of their support has definitely changed. I have an office in the U.S., rather than just here, and they see me potentially as a magnet. They want to build up the company, they see Heyday to be a major supplier to the studio."

The Rowling industry has become such a global behemoth that it's easy to forget that, in Heyman's words, "she is really emblematic of the best of British independence."