Peter Jackson is driven by a deep-seated neurosis: The fear that his films are terrible.

In the beginning, at least.

Now, the director who won legions of devoted fans and Oscar glory with his mega-grossing "Lord of the Rings" movies is facing those fears times three: He has spent the past year juggling aliens, Hobbits and a dead teenage girl in an oddly mismatched trio of major movie projects. And if the sheer workload weren't enough to keep the 47-year-old filmmaker on edge, he's also grappling with lofty expectations.

Chief among them, his own.

"You're always imagining the best, and then you always have to compromise for what you get in the real world," he said.

"It's a process of constant disappointment," he added, "but somehow you have to hope that you set your goals high enough that even with the disappointment, you still end up with something that other people enjoy."

Jackson finished the screenplay for the first "Hobbit" film in August. He wrote the screenplay, directed and produced "The Lovely Bones," set for release in December. And he produced and served as mentor on the recent box-office hit "District 9."

"I get involved in films I'm inspired about," he said. "I get involved in movies that I want to see. That's really the bottom line."

His involvement in "District 9" came through an unsuccessful attempt to adapt the "Halo" video game into a film. Jackson was working with first-time filmmaker Neill Blomkamp when "studio politics" killed the project, so they channeled their energy into "District 9," about aliens being segregated in South Africa. Jackson had not taken on a mentoring role before.

"I thought the best thing I could do was to keep throwing ideas at him, but he ultimately had the final decision," he said.

All the while, Jackson was shooting "The Lovely Bones" in his native New Zealand, a film he describes as among the most dramatic and emotional he has made. He cried when he read the book and knew its profound effect on him made it ripe fodder for the big screen.

The 2002 novel by Alice Sebold tells of a teenage girl who is raped and murdered, then watches from the afterlife as her family grieves and her killer prepares to strike again. The film is "very much my take on the book I read and what that book did to me emotionally," Jackson said.

His other beloved project is "The Hobbit," split into two films that he wrote and will executive produce. He has said the films would rely not just on J.R.R. Tolkien's "The Hobbit," but on stories about its characters in the author's three-volume "The Lord of the Rings," which Jackson adapted into three Oscar-nominated films.

Jackson was pleased at how quickly he was able to re-immerse himself in Tolkien's world. "We just clicked straight back into Middle-earth again," he said.