Melissa Rosenberg

"I didn't want to be that person who ruined Twilight," Melissa Rosenberg said one recent afternoon, days before the movie she scripted earned $70.6 million in its first weekend.

That success has validated, at least financially, her decision to tread lightly on the Stephanie Meyer novel that provided the well-loved source material for the film.

Rosenberg, an executive producer on Dexter whose writing credits include Step Up and The O.C., said she aimed to adapt the book rather than using it as a "jumping off point."

"We knew that if we were true to the book, if we honored it, fans would come with us," she said.

The novel's more than 500 pages had to be condensed to around 100 pages of script. Rosenberg also had to make the interior monologues of the main character, Bella (Kristen Stewart), more cinematic.

"How do you externalize Bella's experience?" Rosenberg asked.

Rosenberg's changes resulted in pivotal scenes in which Bella and her vampire love, Edward (Robert Pattinson), talk in her room, cuddle, and think deep thoughts – while caught up in the fevered intensity of first love.

Another challenge, Rosenberg said, was balancing her creative process with Meyer's work and wishes.

"In a metaphorical sense, it was a very intimate collaboration," she said.  "Once I met her, I realized this is not someone who is going to usurp my creative vision and, more importantly, my creative vision was in sync with hers."

Meyer's approval of the final script was one of the biggest compliments of Rosenberg's career, she said.

While many movies catering to younger viewers pander to their audience, Rosenberg kept Twilight's dialogue spare and the scenes taut.

"My job is, at some points, to get out of the way of the actor, to not overwrite – that's the job of the screenwriter, as opposed to a novelist.

"When I was writing this, I didn't know who was playing [in] it," she continued. "I tend to write with a dark sense of humor – [and] it got on the actors, and felt wrong. There was some adjusting. Going forward [with potential sequels], it'll be more like a TV series, then I'll know who I'm writing for."

Rosenfeld sees plenty of parallels between writing Twilight and writing for Dexter, which chronicles the double-life of a serial killer.

"In both cases there is, at the center, a character who is not human, and seeks to be human," she said. "He passes as human, and is fascinated by humanity. What you get with characters like that is their exploration of what it is to be human, so it's a wonderful exploration, storytelling-wise, of that question exactly, and all the subtleties of it.

"The grandest scope of love and commitment and the smaller things, like physical warmth, that appeals to me. That's what storytellng is at its heart, the exploration of the human condition."

What do you think? Did Rosenberg do a good job adapting Meyer's book?