Ironically, prolific writer William Goldman was a mediocre student in high school and undergrad-- according to a recent interview, when he applied to Columbia University in 1953 at the age of 21, he only got in due to a friend's influencing the college administrators.
Today, Goldman is also one of Hollywood's most highly-paid and sought-after script doctors. In this capacity, he's seldom given official writing credit; he's often listed as a "consultant" or given "thanks". In exchange for his anonymity, he's rumored to get a fee of $250,000 for each week of intensive script work. Some of the films he's rewritten partially or entirely behind the scenes include:
Goldman's writing of Good Will Hunting has been vigorously denied by all involved -- especially the "official" writers, Matt Damon and Ben Affleck, who won an Academy Award for Best Original Screenplay.
I don't buy for one minute that Goldman merely "consulted" or "assisted" with Good Will Hunting -- he wrote the dang thing, and that Oscar should have been his.
Don't believe me? Go rent some of the 30+ other movies he's officially written, like Butch Cassidy and the Sundance Kid (1969), Magic (1978), Heat (1987) or Chaplin (1992). Now watch Good Will Hunting -- it looks and sounds just like a Goldman script, doesn't it? Now, let's look at Affleck's and Damon's other writing credits. Damon wrote a movie called Gerry in 2002, and Affleck wrote a couple of episodes of a short-lived series called "Push, Nevada" that same year. That's all. For a couple of freshman Oscar winners, the lads aren't exactly tearin' it up with their typewriters, are they?
The seven films listed above are probably just a fraction of the movies he's fixed; many a troubled script has been set right and saved from disaster because of Goldman.
On a side note, if you want to read more of his writing on the film industry, check out Premiere -- he often contributes very good articles to that magazine.