The “Harry Potter” film franchise concludes in July as Hollywood’s highest-grossing series ever with the release of the eighth feature, “Harry Potter and the Deathly Hallows: Part 2” in 3D. The first seven films have grossed $6.37 billion worldwide.

“People tell me it is the biggest,” says producer David Heyman, who quickly adds, “until the next franchise.” He had “no idea it would become the phenomenon it has become. I thought, ‘If I’m lucky this might be my ‘Chitty Chitty Bang Bang.’ ”

He can remember exactly the first time he heard about author J.K. Rowling and Harry Potter.

“Somebody in my office read an article about an unpublished manuscript that had just sold to Bloomsbury, a London publishing house. We got a copy and as it was an unknown author it sat down on the bottom shelf in my office until my secretary took it home one weekend.”

At the following Monday morning meeting, Heyman asked, “Has anybody read anything good?” And his secretary said yes. “It’s about a young boy who goes to wizard school.”

That night Heyman “read the whole thing in one evening. The following day I set about trying to acquire the rights and then began the journey.”

That was 1997. “I was a junior producer and I made a promise that I would do everything I could to be faithful to the books and that was the case. And, yeah, the rest is history.”

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