Amazon: How did this project come to you?

Hampton: I had an instinct that the book would make a great movie, and I volunteered for it, but Ian (McEwan), who I knew slightly, looked at my drafts and liked my ideas, so he chose me. I passed the audition, basically.

As a writer, how do you even start to adapt someone else’s material into a screenplay?

It’s made easier in this case that I have done quite a bit of this in the past, but this one was particularly taxing for two reasons: a) it’s an intrinsically difficult piece because it’s about narrative, and that makes it hard to settle on the right form; and b) because conventional wisdom says that a movie is three acts, but the book is two… and the second act is itself three acts (laughs). So it took over two years of work from start to finish, but Joe knew what he wanted and Ian trusted me, so that made it easier.

How do you manage handling so many other people’s expectations? You have to please the author, the director, the producers, and ultimately the audience, all while trying to stay true to your own vision as an artist.

Yes, well, it was a lot of work. As a writer, you’re not looking for models, you’re trying to be original and that can be a challenge. I completed three full drafts while working with Richard Eyre (the original director attached to the project who chose to make Notes on a Scandal instead) and Ian before Joe took over and said "I’d like to start from scratch." So we did, and we set out in a completely different direction. Joe set certain conditions, for one that we stay true to the book and tell the story in the order it goes in the book. But we did make changes in the later drafts, for example we started with Briony narrating the movie throughout, and we cut that as we realized it wasn’t needed to tell the story. So we continued to revise the drafts together.

Last December we rented a little hilltop villa in Tuscany together, and in the mornings we would get together and eat breakfast and talk about the story. Then in the afternoons I walked down to a little cottage at the bottom of the hill and worked on the script, and we’d meet back up at the villa, cook dinner, drink wine, and go over the script together. Joe knew what he wanted and that gave us a clear direction to head in. It was a wonderful way to work, and I think the result is the best draft I’ve done.

There are two particularly strong and memorable moments in the film. One is that incredible extended shot of the chaos on the beach at Dunkirk, and the other is of Robbie (James McAvoy) behind the movie screen, silhouetted in his desperation as the images from Prévert’s film "Quai des Brumes" ( “Port of Shadows”) loom in the background. Did you write those into the script, or were they entirely the vision of the director? And is the genesis of those visual cinematic moments with the writer or director?

The Dunkirk scene was the most difficult one in the film to shoot, and it was actually much more elaborate to begin with, but it was too expensive so it was cut down on paper. Joe’s very good at preparation and at seizing the moment, and as the Dunkirk sequence was originally written as a series of scenes, Joe decided to do it all in one shot, which solved the problem of the expense and it turned out to be a brilliant decision, as you can see on the film. The moment where Robbie is silhouetted on the screen, yes I love that shot. That was written in but Joe and (cinematographer) Seamus McGarvey created such an indelible shot that it really captured Robbie in an unforgettable way at a key moment.

Now that you’ve seen the final cut, would you change anything at all about the final product?

No I don’t think so. In fact I was very impressed by Joe Wright’s rigor. The original cut was 20 minutes longer. We had a scene, for example, on Dunkirk where an RAF pilot gets beaten up by the soldiers, you know because they were so mad because they had no RAF air cover over the beach, and we realized it didn’t fit the needs of the scene so we cut it. But that’s very difficult for a director to do, to go through and cut out what’s not needed, so I really applaud Joe for his work there.

James McAvoy, who plays Robbie, is just getting to be known as a movie star (he previously starred as Mr. Tumnus in The Chronicles of Narnia and as Dr. Nicholas Garrigan in The Last King of Scotland), and Keira Knightley is perfect as Cecilia. Did you have them or anyone else already in mind when you were crafting their parts?

I didn’t envision any particular actor or actress in mind as I was writing the script, but James and Keira are wonderful together, and Saoirse Ronan was a real find for Briony. We were very fortunate to get this cast, but the script wasn’t written with any one actor in mind.

You mentioned earlier that you want to be original, of course, but every artist has influences. Who are yours?

Naturally I love Billy Wilder, the films of Luis Bunuel, Francois Truffaut, and of course Ingmar Bergman. I think their work is so important and they’ve given so much to the cinema that, for me, its impossible to write for their art form and not be somehow shaped by their visions.

The process of adapting a book to a screenplay is not an easy one, and no one knows that better than award-winning screenwriter Christopher Hampton (see our interview with him above). We asked Christopher Hampton, the screenwriter of Atonement, what other books and movies informed his work on the script. He shared with us the following picks.

Quai des Brumes (Port of Shadows) It's Quai des Brumes which is showing in the cinema in Dunkirk where Robbie, the hero of Atonement, finds himself backstage watching giant images of Jean Gabin and Michèle Morgan. These films, written by the great French screenwriter/poet Jacques Prévert, directed by Marcel Carné and marvellously designed in the studio by Alexandre Trauner, create an atmosphere of romantic melancholy and inescapable fate so overpowering, that at one point Quai des Brumes was accused of being responsible for the French losing the war.

The Go-Between Harold Pinter's screenplay for Joseph Losey's 1971 film with Julie Christie and Alan Bates was one of the first screenplays I ever read, in conjuction with the novel (by L.P. Hartley) from which it was adapted. The book deals, like Atonement, with an innocent child's misunderstanding of the sexuality of a adults and the profound and damaging effects this has on the child's adult life. Pinter's screenplay, with its original use of flash-forward, is bold and distinctive, while still remaining a model of fidelity to its source: I certainly learned a great deal from it.

Brief Encounter This wonderfully photographed, beautifully acted, exquisitely written 1945 David Lean film was based on Still Life, a short play by Noël Coward. The essence of British reticence (and, some might say, fear of sexuality) and wartime self-restraint, beneath which the most powerful emotions swirl and rage, it is a compendium of the attitudes and speech-patterns of the day. The director of Atonement, Joe Wright, showed the film to his actors as a reference-point and key to a vanished age.

Suite Francaise This recently discovered novel, unfinished because its extraordinarily talented author, Irène Némirovsky, was arrested by Vichy France and deported to Auschwitz, gives an unforgettable portrait of the chaos and confusions of Occupied France. it shows, in very much the way we're attempted in Atonement, how the experience of a war and an evacuation (in this case, of Paris) in no way modifies the personal obsessions of its cast of characters, who live out as many radically different stories as there are individuals affected.