There's nothing to fear but fear itself, as they say; or in writer-director Christopher Nolan's case, there's nothing to fear but the monstrous expectations of his "Batman Begins" sequel "The Dark Knight."

"The Dark Knight" explores the turmoil Batman/Bruce Wayne (Christian Bale) faces in The Joker (the late Heath Ledger), as his psychotic, new nemesis rises to power in Gotham City.

"Batman Begins" struck at the heart of fear as villains Ra's Al Guhl (Liam Neeson) and the Scarecrow (Cillian Murphy) attempted to disburse a toxin in Gotham City that would induce fear, panic and anarchy in the population. The concept was a brilliant stroke of genius by Nolan and co-writer David Goyer -- which effectively provided them (along with Nolan's brother, Jonathan) the unenviable task of topping the story in "The Dark Knight."

In order to do that, they examined the plan of the nefarious criminal mastermind The Joker. The motivation in "The Dark Knight" was no longer to fear fear itself, so much, but to have Batman and Gotham to fear themselves.

"Batman's internal struggle -- his struggle of taking all of the rage and anger inside himself and trying to channel it into something positive and not let it explode into something negative -- I think that struggle is spread out to all the other characters and citywide in a sense," said Nolan in a recent @ The Movies interview.

"That dilemma -- that central paradox -- is triggered by The Joker and spread to the others, so they're all thinking, 'How far can you go to achieve good?' The Joker's ability to deconstruct their ethical and moral systems, is in a way to expose the hypocrisy or double-standards that lie underneath them," Nolan added. "That makes him an extraordinarily effective anarchist. I think the fear of total anarchy -- the fear of total chaos -- funny enough, as it was at the end of 'Batman Begins' at the end, is one of the most palatable fears that we have."

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And that's especially troubling considering the man whose causing the anarchy doesn't have any fears of his own.

"The Joker is somebody who is not in any way bound by rules or convention of either regular society or criminal society," Nolan said. "He's somebody who has no values and no motivations, and therefore he has no fear of anything because he's not afraid of any consequences. He doesn't acknowledge the existence of any justified consequences or structure that he should adhere to. I think that's the most frightening form of evil that could exist, but it's a very human and credible threat."

In "The Dark Knight," The Joker and Gotham's crime underworld is not only targeted by Batman, but Lt. Jim Gordon (Gary Oldman) and the city's new, hard-hammering District Attorney, Harvey Dent (Aaron Eckhart). Dent, like Batman, walks the fine line between hero and vigilante, which creates his destined path to become the criminal Two-Face.

Nolan's said that Eckhart's inherent "all-American" presence made him a perfect match for Dent and ultimately, his villainous alter ego.

"He has a heroic presence, sort of a young Robert Redford thing going on," said Nolan, who, along with his wife, producer Emma Thomas, casted Eckhart in the film. "But the reason we chose Aaron was not just for that. Like he did 'In the Company of Men,' he's able to take that all-American presence and have a hint of something darker running through it."

To not have that sort of quality wouldn't be giving the audience the rich character they deserve, Nolan said.

"For the story we're telling in 'The Dark Knight,' I thought we wouldn't be playing fair with the audience if we didn't have somebody playing that role who could get across, right from the beginning, the idea that there's something more at work than just a straight, heroic presence," Nolan explained. "There's a little something there that might go one way or the other."

"The Dark Knight" marks the third time Nolan has worked with Bale (they did "The Prestige" together after "Batman Begins"), and the filmmaker continues to be impressed by the actor's natural ability to subtly grow his already complex characters. It's the very reason audiences will still be drawn to Batman and care about the character throughout "The Dark Knight," because, after all, if your audience loses sight of the character, you have nothing.

"I think this what surprised me this time about Christian as I got in the edit suite and put this all together -- and then when I watched the finished film with him for the first time -- was to see how by the end of the movie, he takes back the story completely to the character of Batman," Nolan said. "He makes the story all relevant to the character and makes it his own with a great sense maturity to the character that's grown almost invisibly throughout the story. I think it sneaks up on you, very much, how big his performance is, in a way, and how much is going on in this performance."