David Mamet adapted Barry Reed’s 1980 The Verdict for the 1982 movie. I’m not one of those blind worshippers of Mamet, but you can begin to understand Mamet’s brilliance in his adaptation. There was very little of the novel left unchanged.
One example of the changes Mamet made is the defense’s spy, Laura Fischer, played by Charlotte Rampling. In the book, the same character is named Donna St. Laurent and she is only deceitful for a small portion of the novel, very early on. In terms of literary tension, the novel character is almost a throwaway. Mamet stretches Donna’s deceit out for almost the entire film and makes it the final obstacle to the redemption of Frank Galvin (played by Paul Newman). When Galvin, a drunkard lawyer who is continually pummelled by powerful adversaries (e.g. the Church, the courts, the prince-of-darkness attorney, and even his own clients) learns that his newfound love is betraying him, the build up is already so complete that the characters' own mental pressures makes the audience's heads buzz. You almost want to offer Galvin a drink yourself.
(You might have recently recognized one of Galvin’s trademark lines cribbed by a few politicians. The line: “If not now, then when?”)
The director of the film, Sydney Lumet, delves into how brilliantly Mamet has written the script on the DVD commentary. He rhapsodizes about how Mamet never wastes dialogue or scene for just plot, but how both are continually used to characterize, how Mamet leads us up and down, hinting, pulling, registering details, and delivering a resolution to an almost impossible situation. All this and the movie is on the surface only a courtroom drama. The Mamet-Lumet-Newman tour de force is worth a long essay in itself, but Lumet recognizes the subtlety and power of the script. By my count, Lumet only deviated from the Mamet script three times.
It was said that Picasso could look at another’s painting, figure out what the painter was trying to do and then go home and do it better, which is why when Picasso came to Paris, everyone locked up their paintings. Mamet has performed the same trick on The Verdict.