The novel Brighton Rock, written by Graham Greene in 1938, is one of the most cherished classics of British 20th-century fiction.

Ten years later it was adapted by Greene himself into what is widely regarded as the one of the best British films ever made. So why did I adapt the book again? The truth is, there were lots of reasons. Some were sound, some were quite irrational. In retrospect, this is the “advice” I would hesitantly give to anyone considering adapting a book for the big screen.

1. Don’t adapt a cultural icon
The joke goes something like this: A man and his dog have just watched a film. A fellow audience member jokingly asks the man what his dog made of the movie. The man replies: “He thought the characterization was strong, the story impeccably told and the atmosphere spot on.” “How remarkable!” says the fellow audience member. “I know,” says the man. “Especially since he loved the book.” Adapting a popular novel is like treading on a cherished dream. No matter how reverent or careful your steps, someone’s going to get hurt. Generally, given the commercial imperatives of the film industry, it’s the story and characters that suffer.

Adapting a classic novel is an altogether different thing. It is less like treading on a cherished dream and more like peeing on a national monument. And if anyone’s going to get hurt, it’ll be the moviemaker. That said, I made Brighton Rock because I wanted to bring two of the most original and compelling characters in the history of the novel—Pinkie and Rose—to life for a new generation of cinema audiences. Cultural icons might be sacred, but a black-and-white film gathering dust in a DVD box set won’t keep a story alive for cinema-goers under the age of 40. If you love it, set it free.

2. Do stay true to the book’s spirit
If you’re going to risk the wrath of genuine book lovers or court the condemnation of cultural guardians, then you might as well do it with your vision of the novel. I reset Brighton Rock in 1964 because the novel depicts the collision of innocence and corruption, tradition vs. modernity. It was Greene himself who said that the best a film could hope to do was to stay true to the spirit, rather than the letter, of a novel. It is hard to define what the “spirit” of a novel is, but in the case of Brighton Rock it seemed to be both the place (a hugely popular seaside resort on the southeast coast of England that became a hotbed for gambling and organized crime) and the characters who populate it in the novel (a bunch of down-at-heel gangsters led by the demonic Pinkie). Characterization was central to Greene’s ideas about good versus bad adaptations. And in my case, I wouldn’t have made the movie without an obsessive affection for Pinkie and his gang, all of whom become more or less in thrall to the angelic Rose, a delightfully innocent young waitress who inadvertently becomes the key witness to a revenge killing for which the entire gang could face the death penalty.

3. Don’t court the author’s approval
By which I mean, do not make honoring the author’s vision of his or her own work your primary concern. Unless you’re (a) discussing the book with the author or (b) justifying what once seemed like sensible narrative decisions to the author’s ghost when said ghost taps you on the shoulder in the small wee hours to ask you what the hell you’re playing at. This happens. And might explain what Greene meant when he talked about being true to the novel’s “spirit.”

When Patricia Highsmith first saw Wim Wenders’ adaptation of her novel Ripley’s Game (which, thanks to Dennis Hopper, ended up being called The American Friend) she was less than enamored. Some time later she changed her mind and told Wenders it was a superlative adaptation of her work. Good authors have a refined sense of craft, so are often the first to appreciate the very particular and demanding narrative and commercial perquisites of film. My current project is an adaptation of the exceptional debut novel Before I Go to Sleep, written by S.J. Watson, an author smart and modest enough to want to “leave it to the experts.” An expert I am not, but I suspect an adaptation’s first duty is to be a good film. And that most authors would agree.

4. Do read the novel more than once
Or at least pretend to. I once read an interview with a screenwriter who said he only ever read a novel he was going to adapt once, his rationalization being that whatever he forgot probably wasn’t worth remembering. He must either have a terrific memory or think very little of his source material. I’m constantly going back to the author to find out what his or her solution to a particular narrative challenge is. By the time I finish adapting a book, the novel itself has been everywhere with me for a least 18 months, is covered in notes and highlights and has been inadvertently dropped in the tub at least twice. A source novel should look like a book you were trying to take a degree in. When I was just out of college I told my friend Joel Cohen (not Blood SimpleGarfield, The Movie ) that I wanted to be a writer. He replied: “A screenwriter or a proper writer?” Well put Joel. Show your author some respect! MM

(Image via IFC Films)