CREDIT GRAB.

Two years ago, when James Schamus wrote a screenplay about the angry green mesomorph known as the Incredible Hulk, he had reason to believe that he could get the film made. For one thing, Ang Lee wanted to direct it, and Schamus had worked closely with Lee for years, producing as well as writing or co-writing many of his movies, including "The Ice Storm" and "Crouching Tiger, Hidden Dragon." For another, Schamus was the co-president of Focus Features, a division of Universal Studios, which owned the rights to the Hulk character and was eager to see him onscreen.

But there were also reasons for doubt. Eight successive writers or teams of writers had already spent seven years trying to craft a screenplay that would satisfy Universal. Adapting a superhero saga is a constraining task: you must write an "origin" scene that explains how the hero got his powers (the boyhood accident involving a dairy barn and a leaky beaker of plutonium which creates . . . Milkman!); every ten pages you have to throw in a "whammo" (the producer Joel Silver's expression for the explosions and car chases that keep audiences munching popcorn); and the movie must end, after a protracted struggle, with the supervillain gloating over the all-but-dead superhero--who suddenly deploys his powers in a hitherto unimagined way.

The earlier plotlines ranged from having Bruce Banner, the Hulk's mild-mannered alter ego, hang out with a delinquent teen-age sidekick in Las Vegas to having him undergo experiments for a mission to Mars. Every notion had been found wanting. But Schamus, who says that he essentially started from scratch, believed that he'd devised a new way in. His Bruce Banner is a mournful scientist who "Hulks out" after an accident exposes him to a massive overdose of gamma rays and "nanomeds" (which are tiny . . . well, it's very complicated). Banner winds up battling his long-lost father, "the Father," a rogue scientist who travels with a pack of mangy, genetically altered "Hulk dogs." Schamus's script was a weave of dreams and flashbacks, a Nietzschean meditation--punctuated by whammos, naturally--on the temptations of rage which also put forward the psychotherapeutic suggestion that men must kill their fathers, one way or another, to grow up:

He walks toward his son, reaches out with his manacled hands., , BRUCE BANNER, No. Please don't touch me. Maybe, once, you were my father. But you're not now--you never will be., , FATHER, (Beat.) Is that so? Well, I have news for you. I didn't come here to see you. I came for my son., , Bruce looks up at him, confused., , FATHER (cont'd.), My real son--the one inside of you. You are merely a superficial shell, a husk of flimsy consciousness, surrounding him, ready to be torn off at a moment's notice.

Cue Banner's inner child: the Hulk!

Universal promptly approved Schamus's draft, and Ang Lee finished shooting the hundred-and-thirty-seven-million-dollar movie last fall. Then it came time for Schamus to receive credit for his work, a responsibility that falls to the Writers Guild of America, the union of television and film writers. After a film wraps, the studio--which is, for copyright purposes, the film's "author"--sends the Guild a "notice of tentative writing credit." But any writer on a film can demand that the credit be arbitrated, and arbitrations are automatic if one of the credited writers is a producer or director of the film (the presumption being that he might have abused his authority to fiddle with the studio's tentative credit).

Of the two hundred and ten films submitted to the Guild last year, sixty-seven, or nearly a third, were arbitrated. The procedure requires that three anonymous Guild writers read all the screenplay drafts that the writers seeking credit want them to consider. (Following a recent rule change, this material is submitted anonymously, too: "Screenplay by Writer A," "Writer B," and so on.) The arbiters also read statements that the writers have put forth in support of their claims. Then they compare the individual drafts with the final shooting script to determine who wrote what. The Guild's credit standards are complex, but, generally speaking, writers of a screenplay adapted from another source, such as a novel or a comic book, need to have written at least thirty-three per cent of the shooting script to get a screenplay credit, while rewriters of an original script need to have contributed at least fifty per cent. The writer of an original screenplay is guaranteed at least a share of a "story by" credit--a lesser credit often awarded to those who lay out the basic plot and theme--no matter how much the script is rewritten. If a writer believes that the arbiters misinterpreted the rules, he or she can appeal the decision to a W.G.A. Policy Review Board.