LOS ANGELES Is it fair to bring so much expectation to "Inception"?

Director Christopher Nolan's follow-up to "The Dark Knight" — which, until "Avatar" came along, was the second highest-grossing film in American history — doesn't just have to reach certain financial thresholds in many people's minds. Thinking adult moviegoers have also now tasked the complex, dream-invasion thriller with saving a dumber-even-than-usual Hollywood summer from abject infantilism.

Those are two huge, somewhat contradictory goals in this era of cinematic cartoonishness. Even though "Inception" represents a labor of love Nolan started writing 10 years ago, he doesn't feel the final result will be too obscure for a mass audience.

It is, after all, a hybrid of two popular genres, science fiction and caper films. While "Inception's" mind tricks and perception bending may not be quite as intellectually stimulating as those in Nolan's breakthrough arthouse hit "Memento," he's certainly proven artistry and intelligence need not be sacrificed with his Batman movies.

"Having the fate of the entire movie industry resting on it seems a little unfair, actually," Nolan overstates, for effect, in the understated English manner. "The negative of that is everyone keeps asking me, 'Do you think it's too smart for summer audiences?' The positive is, they're going 'There's nothing else like it out there.' I can't say what is going to happen box-office-wise or all the rest.

"But I think 'Inception' has a lot for people to be super-entertained by. When I watch the film, it doesn't feel brainy and small. It feels like a big, old-fashioned entertainment — but yeah, one founded on new and fresh ideas."

The film is set in the near future where the hot new method of corporate espionage is to enter a competitor's dreams via drugs and a rather low-tech-looking device. Once a team of hired professionals does this, they manipulate the sleeper's unconscious scenario to get the information hidden in his brain — or, as is the case with "Inception's" main storyline, attempt the much riskier gambit of planting a notion that will influence the dreamer's future waking actions.

Leonardo DiCaprio plays Dom Cobb, the leader of one of these covert outfits, who's having some trouble with his own subconscious. His deceased wife, Mal ("La Vie en Rose" Oscar-winner Marion Cotillard), keeps popping up in the middle of assignments, a femme fatale manifestation of Dom's guilt bent on sabotaging the missions.

That alone would be heady enough stuff for your average Hollywood action spectacle. But it's just one of many narrative facets "Inception" viewers better keep track of or else lose their way.

Those with working attention spans should, however, appreciate how carefully Nolan has worked out his dreamworld logic and kept the surrealism within the realm of comprehensibility.

"It's a very existential, big Hollywood film, and that's something that I haven't seen very often," DiCaprio notes. "In somebody else's hands, this movie could've been a catastrophe.

"When you're dealing with dreamworlds and entering people's subconscious and trying to infiltrate four different layers of unreality, it opens the possibility for anything to happen. So you have to create and construct a narrative that is compelling and suspenseful, or you could end up floating around in a pink wonderland that makes no sense."

Despite such signature images as a locomotive barreling down the middle of a rain-drenched Los Angeles street and Parisian city blocks folding up on themselves at 90 degree angles, Nolan tried to keep the dreamscapes fairly relatable to all while making each one distinct from the others.

"It took a lot of production work to distinguish between layers of dreams," the director says. "We decided early on that we didn't want to do any sort of formalist differences, tinting of the image or this, that and the other. So what we decided to do was construct visual differences in each actual world, so it's raining or it's a night interior or a snowscape. The whole movie rests on a massive amount of cross-cutting in the last act, so you want to be able to identify, from a close-up that you just jump into, exactly where you are."

That said, perceptual disorientation is key to both dreams and to "Inception's" most impressive effects. Perhaps even more memorable than the train and folding Paris bits — which, by nature, required the kinds of computer graphics Nolan generally resists using in his naturalistic film fantasies — is an all-practical fight in a rotating hotel corridor.

Built in the converted British airship hangar that Nolan has often used for a soundstage, the 100-foot-long hallway was suspended by eight huge, concentric rings that could turn a full 360 degrees. Joseph Gordon-Levitt, who plays Dom's meticulously dressed and prepared Lt. Arthur, fought stuntmen representing a defensive subconscious on wires while the shifting walls enhanced the hallucinatory weightlessness of the situation.

Gordon-Levitt, who trained to pull off the scene's physical demands, says the real key was remembering that Arthur was engaged in psychological combat.

"I wanted to do the sequences as the character," the grown-up "3rd Rock from the Sun" kid says. "He's very particular, fastidious, thought-through; he remains a step ahead of everything. And in these action sequences, he's dreaming, it's a mental thing. It's not like he can take on all of these physically bigger guards. But he knows he's dreaming and is, in effect, keeping his own subconscious in control. So it was about remaining calm, kind of cold stone efficient."

Such approaches mitigate the movie's fundamental mind-boggling effect. Rational as it strives to be, Nolan realized that "Inception" had to have a strong emotional core in order to keep audiences engaged. That's where Cotillard's Mal came in.

"It's a very complex character," the French actress says. "But she touched me right away and I felt that I could understand her. She has so many people inside of her, and she's lost in different worlds just because she's totally lost inside of herself. She's a woman in love, she's a woman who's struggling and she's a struggle herself between a lot of opposite things."

When it came down to it, an understanding of the emotional issues at stake proved much more important than familiarity with the clinical history of dream interpretation.

"At first, I tried to take a traditional approach to the dreamworld and the character, but then I realized that this wasn't that type of movie," DiCaprio admits. "I read Jung and Freud, studied analyses of dreams. The most that I could extract from it was that, at night, when our mind's at rest, things that we've suppressed — emotions, thoughts, ideas — come to fruition. But to put that in scientific terms or try to give it a set of rules doesn't work.

"So I had to go to Chris and say, 'You develop your very specific dream worlds and develop your rules for them, and make my character's journey fit within them.'u2009"

This might be a great filmmaker's personal project, but Nolan would like it to be a hit. (The film took the top spot at the box office last weekend, earning $62.8 million.)

"What I'm finding as we've screened 'Inception' is that most people have no trouble following it whatsoever, but sometimes they worry that they have," Nolan says. "Or, they worry that other people won't.

"What I want to try and tell people is to just relax and enjoy the movie. If you do that, you'll get everything you need to get.

"'Memento' was exactly the same. People who just let it wash over them completely got it. They got that there were times when you were meant to be confused, but if you didn't worry about it, you caught up. This is very much the same, but on a bigger scale as an action movie."