'Harry Potter' Author J.K. Rowling Describes Future Plans

July 16, 2009— -- It is Jan. 11, 2007. The author is putting the finishing touches on her latest manuscript. She adds page numbers, saves the document on her computer.

It's almost impossible to describe the level of expectation surrounding this one writer, this one book. The finished product is now the most valuable manuscript in publishing history.

"Well, you don't know, it might be rubbish," joked J.K. Rowling, the world-renowned author, about the seventh and final installment of her "Harry Potter" series, "Harry Potter and the Deathly Hallows."

Rowling talked about the book in an interview with filmmaker James Runcie obtained by ABC News.

"Some people will loathe it, they will absolutely loathe it, but the thing is, that's as it should be, because for some people to love it, others must loathe it," she said. "That's just in the nature of the plot, some people won't be happy because what they wanted to happen hasn't happened."

As "The Deathly Hallows" made its way to publication July 21, 2007, Runcie conducted repeated interviews with Rowling, tracking a year in the life of one of the most successful authors of all time. The "Harry Potter" series has sold more than 400 million copies around the world, and earnings for the first five movies -- the sixth movie in the series landed in theaters Wednesday -- have reached $4 billion.

Click HERE for Part 1 of the J.K. Rowling story.

Her success as a fiction writer has delivered Rowling from a life on the dole as a struggling single mom to a life of unimaginable wealth and celebrity. Now, she says, her days revolve around balancing her family life with the demands of work -- and, she says, exploring new directions in fiction.

Watch "J.K. Rowling: A Year in the Life," Thursday, July 16 at 8 p.m. ET on ABC.

Rowling's publisher holds a meeting to plan the launch of "The Deathly Hallows." Discussion turns to how many copies Rowling will be able to sign. One-thousand? Two? The author agrees to sign for eight hours.

"To an extent, there's so much expectation from the hard-core fans, I'm not sure I could ever match up to it," Rowling told Runcie. "But I'm really happy with [the new book], I like it, and I don't always feel like that."

In a factory in Suffolk, under conditions of extreme secrecy, the last book is printed. On July 20, 2007, at the Natural History museum in London, 1,700 people picked out of a lottery of 90,000 applicants await Rowling's arrival.

"I can't believe I'm here. I'm even more excited than I thought I would be," Rowling says on the way to the event. "I also really, really want a cigarette right now, and when I said that to [husband] Neil, he said, 'Have you got one?' and I should have done ... but then I would have been hooked and tomorrow I would have gone out and bought 20, I am, I can't smoke, it's... with me it's 40 a day or it's nothing."