David Heyman: The books lead us. I mean, we're in a good position of having Jo Rowling provide us with fantastic sorts of material.

Steve Kloves: All you have to do is read the book to kind of, I think, sense the place. It's, you know, tone and atmosphere -- which I thought she'd done, and continues to do, so grand.

David Heyman: In the very first one, Jo came to the set when we were designing, coming up with the design, and had a look-through of them to make sure we weren't wildly off.

Mark Radcliffe: Jo created this world, we wanted to stay true to it and organic to it, and that's been our mission.

David Heyman: All that vision is born very much from the book. Part of the universe that first Chris, and now Alfonso, has built upon.

Alfonso Cuaron: From the get-go what I was aiming at was serving the material.

Jo Rowling: Out of the five books I've published, writing Azkaban was the easiest, and in some ways I think that shows. Although it's the tricky part in some was, as Alfonso will really appreciate, and Steve Kloves, as the script writer, will really appreciate, because they've kind of had to negotiate the same ascent that I had to negotiate. At the same time, I felt I was really given space to do that, so I -- so it was an enjoyable process.

Alfonso Cuaron: The moment that I read the book I-I just felt so connected. I ... for me, everything was so clear how it should look as a film, and how it should be told as a film.

Steve Kloves: We tried to discover the best way to convey what Jo was expressing in the page, in movie terms. And um, that lead us to some interesting places.

Alfonso Cuaron: You deal with so many abstract concepts, like the time traveling. It is so ... such an abstract thing, and it is so difficult, that even trying to explain it right now....

Jo Rowling: Yeah, it's hard.

Alfonso Cuaron: ...is hard.

Jo Rowling: It is hard, 'cause you just go in circles.

Alfonso Cuaron: But then in the book, everything just makes perfect sense.

Jo Rowling: I loved watching that part of the film, I loved watching the time turner sequence. There was just enough humor in it, just enough nearness is ... Dumbledore's comment when they come back is just perfect.

David Heyman: When we got to Scotland to meet with Jo -- one, I think it's important for Jo to feel comfortable and two, I think that jo is a wonderful source of information and is incredibly generous with us.

Chris Columbus: I remember when she walked in the door, for some reason I expected to meet someone who was like seventy. Jo walked in, she was younger than I was, we liked the same films and we liked the same music, and it was just an immediate connection.

David Heyman: When she met Alfonso, he talked about his vision for the film, talked through many ideas.

Jo Rowling: Alfonso was mentioned very early on, and I was really enthusiastic about the idea -- and I loved "Y Tu Mama Tambien." Alfonso just obviously understands teenage boys backwards and everything, at 13 now.

Alfonso Cuaron: these kids were starting to take themselves seriously as actors, so they were willing to explore more emotional territories. I was so lucky that I had them so raw and so willing to go there.

Jo Rowling: I think all three of them give their best performance to date.

Alfonso Cuaron: Poor Malfoy....

Jo Rowling: He deserves it, though.

Alfonso Cuaron: ..he deserves it.

Jo Rowling: Tom took that punch really well.

Alfonso Cuaron: He, oh....

Jo Rowling: He really did a good job on that.

Alfonso Cuaron: Oh, they loved it. Emma was looking forward for that moment, and I remember Tom telling Emma, "Oh if you want to hit me, just hit me, just hit me."

Jo Rowling: What a hero.

Alfonso Cuaron: The universe that you created ... you know every corner of that place.

Stuart Craig: This was a map of the world. This drawing is Jo Rowling's drawing, that she executed in just a few minutes. As you see, it has all the principle ingredients. The Dark Forest is here, the Whomping Willow, the Quidditch Pitch, Hogwarts Castle itself. The Black Lake is there, the perimeter road, Hogsmeade Village. She had a very, very exact and precise understanding of her world and her creation. She knew exactly the relationship between all of the elements, she was able to give it to us - and that became our Bible.

Alfonso Cuaron: We needed a place where the kids could see the execution of Buckbeak, and we thought about having a graveyard. And we consulted Jo about it and she said "No, the graveyard is not there," and I said "Why?" And then she gave me the whole explanation of why the graveyard cannot b there, because it's in a different place of the castle. Because it's going to play...and she knows her thing, she knows exactly what's going to happen later. And once I remember having little people in some storyboards, playing some keyboards and an organ in the Great Hall. And Jo said "No, there are no little people in this universe." I said "Yes, it's like..." she says, "Yes, lovely image, but they don't make sense in this universe."

Jo Rowling: I was really mean; I wouldn't let him do it. That's not fair, is it?

Alfonso Cuaron: She was just about trying as much as possible to serve the story and the spirit of the story, because that's what is great of the book. Because the third book is, for me, so abstract and deals with so many abstract concepts - but at the same time, it's in the frame of an adventure.

David Heyman: I think it's very, very important that Alfonso Cuaron be allowed to make this his own film. It's important that any director come into a situation like this and feel the freedom, feel empowered to make it their own, that's how you're going to get the best films.

Alfonso Cuaron: Pretty much all the decisions, all the visual decisions, were made as we were shooting and not in the cutting room. We made most of those decisions either in the storyboard or while we were blocking the scenes with the actors, working with the actors, and we decided how to approach the scene.

David Heyman: What he's done is he's built from the foundations of the books, built from the foundations of Chris Columbus, who captured the first two, but made them very much his own to serve the story.

Jo Rowling: Alfonso had good intuition about what would and wouldn't work. He's put things in the film that, without knowing it, foreshadow things that are going to happen in the final two books. So I really got goosebumps when I saw a couple of those things, and I thought people are going to look back on the film and think those were put in deliberately as clues.

Steve Kloves: Jo wants the movies to be faithful to the books, on the other hand, she realizes that they're completely different mediums. To be entirely faithful, these movies would be sixteen hours long.

Alfonso Cuaron: In this film, the film was about a child trying to find his identity as a teenager. We found the theme, and then whatever stuck there we kept, and whatever didn't ... sorry. As long as we didn't affect or contradict either the universe, or what is to come.

Chris Columbus: My biggest concern for the visual effects, I want to make absolutely certain that the visual effects would again move up a notch from the last film. First film, we were fairly rushed and the effects were never up to anyone's standards. In the second film, we improved them greatly, and I wanted to take another leap in this film.

Alfonso Cuaron: We're watching it and it's like "Wow, that hippogriff, he looks great." And we're just praising the conceptual artists and the CG artists that put it together, then someone said "Yes, but don't forget who imagined it in the first place." And here she is.

Jo Rowling: I think it's important to say I didn't invent the hippogriff. I invented that hippogriff, but the creature the hippogriff, as you know, is in folklore and mythology, so that's not my creation. But I really thought hard about this, because it could've been, in the book, it could've ben an absurdity. And indeed, it really could've been in the film as well, but I thought you made him a real creature.

Alfonso Cuaron: There are not that many graphical representations of hippogriff, and that is something with the story that is very interesting. There are sphinx, there are several sphinx, or you see creatures that are half bird and half cat, a lot of different things. But for hippogriff, it was actually hard to find....

Jo Rowling: I knew that 'cause I went looking.

Alfonso Cuaron: You knew that, yeah.

Jo Rowling: I could hardly find any anywhere.

Alfonso Cuaron: No, I know.

Jo Rowling: So I thought it's complete liberty to invent. I had a nightmare in my teens, in which I saw hooded, gliding figures. They could almost be figments of your imagination in a sort of tortured imagination, as indeed they are. But you know what I mean? They could be figments of a mentally ill mind. And um, that was the thing that I was expecting in the book. Harry's particularly vulnerable to them, but he's got a much worse post, so he would be. You know it's not weakness, it's just the fact that he's faced more.

Chris Columbus: I think Alfonso came up with an amazing design for the dementors, because they truly are unlike anything you've ever seen. They are sort of a close cousin to maybe what we've all perceived as death over the years, and that's very, very frightening.

Jo Rowling: I thought the shrunken head was very funny, I really liked that. It was all done really well, and it was a really funny idea. I mean, I've said to Steve Kloves many times "Dammit, I wish I could've written them up." You know? But obviously that's what you want. You want to be working with people who come up with great stuff, it's great you know, when I'm looking around for all these little bits that are completely consistent with the world. But I, you know, there you go.

Chris Columbus: For me, one of the great memories was sitting in a room with Steve Kloves, Jo Rowling, and David Heyman, the producer. Just the four of us for several weeks discussing quidditch, talking about what it's going to look like. That excitement, that sense of making something really special, was something I took with me through the making of the first film and the second film.

Steve Kloves: The overall process is incredibly open, and incredibly creative.

Jo Rowling: I think in this case, the book and the director were really made for each other. There's a unity about the film, there's a consistency..its tone, its feeling, that's very, very enjoyable for me - and that's not a very easy thing, for the author of the original material. I'm completely happy, what more can I say?