In the second part of my series of interviews with the cast and filmmakers behind this summer's much-buzzed-about Inception, writer-director Christopher Nolan's follow-up to The Dark Knight, I sat down with star Leonard DiCaprio. As I said in my last piece, very few people have any real sense of what Inception is about, a state of ignorance I'd like to encourage as I think the actual experience of the movie can't be described. But posters, billboards, and marketing have already made it clear that the movie uses the dreaming world as a set piece and that Leo and his cohorts -- played by Ellen Page, Joseph Gordon-Levitt, and more -- have some degree of expertise in navigating the mind. Nothing here should qualify as spoilers unless you've been living under a rock for the past six months.

Cole Haddon: Leo, what's your relationship with dreaming like? Are you a big dreamer? Is it a subject you've long been interested in?

Leonardo DiCaprio: You know, it was interesting being part of this film, because I'm not a big dreamer. I never have been. I remember fragments of my dream, and I tried to take a traditional sort of approach to researching this project and doing preparation for it. I read books on dream analysis, Freud's book on the analysis of dreams, and tried to research it in that sort of form. But I realized that this is Chris Nolan's dream world. It has its own structure and its own set of rules. And doing that, it was basically being able to sit down with Chris for two months every other day and talk about the structure of this dream world, and how the rules apply in it. The only thing I've sort of obviously extracted from the research of dreams is that I don't think there's a specific science you can put on dream psychology. I think that it's up to, obviously, the individual. Obviously, we suppress things, emotions, things during the day -- thoughts that we obviously haven't thought through enough, and in that state of sleep when our subconscious or mind just sort of randomly fires off different surreal story structures, and when we wake up we should pay attention to these things.

CH: There are several layers of reality -- or, I guess, dreaming -- that the characters in Inception pass through. It makes the movie impossible to walk away from, because you'll immediately lose your bearings as Ellen Page's character does when she frantically asks whose dream the characters are in after forgetting. Were there ever any moments where the story became so complex that you also lost track of where you were in terms of it?

LD: What was very interesting for me was reading the original screenplay -- and obviously this story structure was extremely ambitious in the fact that simultaneously you had four different states of the human subconscious that represented different dream-states, and each one affected the other. What ... was startling to me in how complicated the screenplay was, was seeing it in a visual format. That's the magic of moviemaking. You clearly identify one scenario with the other, and it's a completely different experience. The snow-capped mountains of Canada, or whether you're in a van or an L.A. elevator shaft or Paris or London -- you experience it and you have a visual reference [for which dream-state you're in]. And it was a lot easier to understand than I ever thought it would be. And that's a testament to how engaging movies are, and the visual medium is.

CH: You're notorious for being drawn to morally ambiguous characters. What drew you to playing Cobb, the leader of Inception's -- I guess you'd call them -- dream raiders?

LD: Well, look, like I said before, this was an extremely ambitious concept that Chris was trying to pull off here. He accomplished it in flying colors. There's very few directors I think in this industry that would pitch to a studio that they wanted to do a multilayered, almost at times existential high-action, high-drama, surreal film that's sort of locked in his mind. And then have an opportunity to do that, and that's a testament to the work he's done in the past. Watching his work and certainly in Memento and Insomnia, he's able to portray these highly condensed, highly complicated plot structures and give them emotional weight and have you, as an audience, feel fully engaged along that process. So, for me, it was a matter of sitting down with Chris and being able to really form the backbone of a character that had a real sort of cathartic journey and really had almost created a scenario where it became like a giant therapy session. At the end of the day, these different layers of the dream do represent a psychoanalysis, him getting deeper and deeper and closer to the truth of what he needs to understand about himself. That in its own right is immediately intriguing, and Chris and I got to work and talked a lot about the different concepts of that and what Cobb has been through in the dream world, what his past is, and certainly what Marion Cottilard's character [Leo's love interest of sorts] represented. I had a lot of wonderful talks with Marion as well about some of the sequences at the end that start to become very surreal and disturbing at times. So, as we were talking more and more about the character, it all became more and more exciting. I think all of us [involved] mutually felt like this was a journey that we had to be a part of. It was extremely exciting.

CH: You just described Cobb's story arc as a form of psychoanalysis, and you've previously referred to your work on Shutter Island also as a sort of therapy session. When you're playing a character operating in a dreamed world, how does that change your performance? And when you do two movies like Shutter Island and Inception back to back, does one influence the other?

LD: It was something I certainly was aware of, but as far as both of them being locked in this dream world, and like I said, going on some kind of cathartic journey throughout the course of the film, that's about where the similarities ended. This film couldn't have been more vastly different than the other in its execution, so I felt safe and completely aware of trying my best not to repeat any of those themes. But to answer your question about how one acts in that world or that there's something you need to be aware of or do different, I would say absolutely not, and that's what was exciting about even attempting, you know, this was my first science-fiction film. The earliest conversations I had with Chris were about how both of us have a hard time with science fiction. We have a little bit of an aversion to it because it's hard for us to emotionally invest in worlds that are too far detached from what we know. That's what's interesting about Chris Nolan's science-fiction worlds. They're deeply rooted visually in things that we've seen before. There are cultural references and it feels like a world that is tactile, that we understand, that we could jump into and it's not too much of a leap of faith to make. But emotionally, as far as the character's journey, I took everything as if it was -- you know, you have to. Otherwise you're not invested in the character, you're not invested in the character's journey, and you know, you're not going to make it believable to an audience. Everything is real, in essence.

CH: Getting back to the type of characters you choose to play, Cobb is chameleonlike with plenty of secrets. Many of your characters seem to be. Are those the roles you're attracted to, or are they just the ones that people pitch to you?

LD: I don't really question when I read a script. If I feel I can be of service to that role, if I feel like it emotionally engages me, it's something that interests me, and obviously if the director is somebody that has the capacity to pull off the ambitious nature of whatever they're trying to do in the screenplay, I never question that. So I guess a lot of my films have been more serious in tone, but that's something that I don't try to deny. Look, I'm a very fortunate person. I get to choose the movies that I want to do. I have a lot of friends in this industry that don't get to do that. I grew up in LA. A lot of my friends are actors so I realize every day how lucky I am to have this opportunity, so while I'm here, I'm going to try to do exactly what I want.

CH: I brought up Shutter Island because I think it and Inception share many parallels in terms of cinema as psychoanalysis. Would you consider them bookends in a way?

LD: Bookends? I don't know. I think that, like I said before, these were characters and filmmakers and plot structures that I was compelled to do and I'm lucky to be able to do, so I jump on those opportunities. I traditionally have always tried to work with the best directors I can. These types of films that are psychologically sort of dark at times, I find extremely exciting to do because there's always something to think about. There's nothing more boring than to show up on set and say a line and know that your character means exactly what they say. It's interesting to have an unreliable narrator in a film and that's what both of those films have been. Both these characters are unreliable to themselves and the characters around them. So that sheer notion was extremely exciting to me.

CH: You're playing J. Edgar Hoover, right? I imagine his story meets the qualifications you just listed.

LD: Yeah, I'm talking to Clint Eastwood about playing J. Edgar Hoover, who had his hand in some of the most sort of scandalous events in American history -- everything from the Vietnam War and Dillinger to Martin Luther King and JFK. It's about the secret life of J. Edgar Hoover.

CH: What about his private life?

LD: Yes, that will be in there definitely.

CH: Does that mean you'll be wearing a dress? [Hoover apparently liked to put on dresses, for those of you not familiar with his part in American history].

LD: Will I wear a dress? Not as of yet. We haven't done the fittings for those so I don't think so.