
If you read the novels and dissect how Stewart distilled and structured the stories, how he cleaned up the narratives, you realize what an art form screenwriting can be. In Patriot Games, for example, the red wigged crack shot Annette was created for the film. Played by the painfully beautiful Polly Walker - picture of her above left after she had just knocked off a bothersome IRA brigade leader - she was also the thread that linked the various stories together and the vital clue that pushed towards the denouement. If she was in the novel at all, she was a passing mention as an arrested red headed “assassin”, but certainly not a fully developed character and a vital thread to the story.
There are hundreds of such details in Stewart’s film adaptations. He helped make the films carefully crafted works. I have read that Tom Clancy was very upset at the film adaptations of his books, but Stewart’s adaptations are tighter than the novels.
Revisited 28 December 2020: I have just read (fellow Hungarian descendant) Joe Eszterhas' The Screenwriter as God! and came across this, "Steve Zaillian wrote the script of Patriot Games that we shot... eighty percent of what was shot was written by Steve Zaillian." Attributed to Patriot Games' Director Phillip Noyce. If this is true, my apologies to Steve Zaillian. I might have gotten this one very wrong.