Here is an interesting quote from Michael Mann on his approach to screenwriting:
Screenwriting 101: Michael Mann
"All right, let me try an example. A story about a guy who's been a bootlegger and a gunman who's retiring to a rural part of the Midwest. There were some political conflicts in this area; an interesting alignment of forces between the KKK and mine owners on one side, and organized labor, immigrants, and bootleggers on the toher. This guy found himself caught in the middle, became a reluctant gunfighter, and killed a man who was the leader of the Klan in his region. He himself was wounded and died in the skirmish. True history Now, go make that into a story.
Well, how? Where do I start? If you do it the way I just told you, it's like any number of bad screenplays. This is a linear biopic: this happened, that happened, this happened, that happened. That's not a story. A story is, he dies. We don't want to do a linear biopic, so let's have an investigation. In the process of investigation with multiple detectives, I can break down into its component parts the true history of Hearst -- call him "Kane" -- and I can arrange the sequence of all these encounters without regard to chronology. I don't have to move through time in a linear fashion. I can cut to either investigator investigating whatever aspect of his life I want to reveal. I can go present, I can go three weeks ago, twenty-six years ago, back to four years ago; put it in any fashion I want. I've liberated myself from the tyranny of chronology by inventing the narrative."
-- Michael Mann (Manhunter, Heat, The Insider), excerpt from "Screenwriters on Screenwriting," edited by Joel Engel