The writer/director's superb adaptation of Upton Sinclair's classic novel

Paul Thomas Anderson has had an inspired career as a filmmaker so far. Hard Eight, Boogie Nights, Magnolia, and Punchdrunk Love have made Anderson a critical darling. He adds to his brilliant portfolio with his best film yet, There Will Be Blood. Loosely based on Upton Sinclair's 20's novel "Oil", Anderson's adaptation follows the exploits of ruthless oil baron Daniel Plainview. Played brilliantly by Daniel Day-Lewis, Plainview is one of cinemas most misanthropic characters. A parable of greed and treachery, There Will Be Blood is mesmerising.

What inspired you to make a film based on the Upton Sinclair novel, "Oil?"{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:The inspiration from the movie comes first and foremost from the book. I had been trying to write something, anything, just to get something written. I had a story that wasn't really working that was about fighting families. It didn't really have anything. It just had that premise. When I read the book there were so many ready-made scenes, and the great venue of the oil fields. Those were kind of the obvious things that seemed worth making a film about. The desire to work with Daniel [Day-Lewis], once that presented itself as a possibility, it certainly drove the engine for me to write it and finish it and get it to him.

Why did you choose a different title for the movie?{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:I changed the title because at the end of the day there's not enough of the book probably left to feel like it's a proper adaptation of the book. I wrote the title down and it looked really good. I grew up in California, and there's a lot of oil out there. I don't live that far from Bakersfield, which is where the initial discoveries of oil were in California. They're still pumping away. I suppose I've always wondered what the stuff is, how we get it out of the ground, why we like it so much and what the story was. The story of oil in California in particular, and in this country, was really well-told in the first couple 100 pages of the Upton Sinclair book. He started to write the book in the '20s when he went with his wife to the Signal Hill area, which was essentially set up to be vacation homes overlooking the Long Beach bay. Somebody decided instead of building vacation homes it was time to start drilling for oil, and they struck oil. So this community went absolutely mad. When Sinclair witnessed this community trying to get this lease together, he said he witnessed human greed laid bare. He saw these people go absolutely crazy. He knew what he wanted to write about. And that's what started him on the road of that story. We just picked up where he left off. At the core of the story was the drive and ambition, not only from this independent oil man but also from the people that he was supposedly getting the better of in leasing their land.

There's a lot of hard and dangerous work that the characters do throughout the film. Was there anything that you wouldn't let Daniel do because of the risk?{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:Nothing! He was required to do it all.

Paul [Dano]'s characters has an underlying socio-political commentary of class warfare and religious issues. How aware were you of this?{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:Aware of it enough to know that if we indulged it or let that stuff rise to the top it could get kind of murky. It's a slippery slope, when you start thinking about something other than just a good battle between two guys who see each other for what they are. Just to sort of work from that first and foremost and let everything that is there fall into place behind it.

Did you cast Paul Dano as Eli/Paul Sunday because of his work with Daniel in The Ballad of Jack and Rose?{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:It was, because the first time I had seen Paul was in The Ballad of Jack and Rose. I called Rebecca Miller [the director and Day-Lewis' wife] to tell her how much I loved the film and to tell Daniel how much I loved the film. But really the first question on my mind was 'Who the hell was that?' I thought he was so terrific. I had originally, insanely thought that we should have a 12 or 13 year-old boy. And that kind of seemed ridiculous. He certainly got a good recommendation from Rebecca and from Daniel. I had to meet Paul for myself to know, and it was pretty clear that he was a terrific young actor.

Originally Paul Dano was only supposed to play the role of Paul Sunday, and then it was expanded for him to play Eli. What made you decide to do that?{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:We had an actor, and it didn't really work, out, and we had Paul, and he was in a small part. We thought, 'God, why is he in such a small part?' And then, better yet, maybe because of my obsession with "East of Eden, I thought, 'Well, they've got to be twins, right?' I had actually been talking to a friend at the moment that all this was happening, who was telling me about his twin brother. I thought it was too good to pass up.

How did you prepare for the big confrontation scenes between Daniel and Paul? What went into filming them?{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:We didn't rehearse it. We just knew where they would stand and had a couple of cameras rolling. We decided to get the scene before the slapping starts, and then we would start slapping. But Paul either forgot or decided to take his own initiative and slap Daniel across the face.

The score is really interesting. How did you get Jonny Greenwood to score the film?{@@@[email protected]@@}{@@@[email protected]@@}Paul Thomas Anderson:It sort of begins and ends with Jonny Greenwood. I suppose the good idea that I had was to ask him to do it. He had a couple pieces that existed before that he'd written for orchestra. He's better known for his day job. He's in a band called Radiohead. He has written a few orchestral pieces that I heard and thought were terrific. I had known him for a few years and asked him to do it, and showed him the film. He said 'OK, great.' I gave him a copy of the movie, and about three weeks later he came back with two hours of music. I have no idea how or when he did it, but he did it. It's kind of amazing. I can't say that I did any real guiding or had any real contribution to it. I just took what he gave us and found the right places for it. A couple of things that he'd written on piano that we then took to an orchestra, a couple things that he'd written for string quartet that just went straight into the film. We did that over the course of a couple months. It was a great experience working with him.