I wanted to sue on Thomas Harris's behalf!
Ahh...but there's the problem. Author's novels don't just get stolen away to make unauthorized movies. Harris sold the rights to his novel back before they made Manhunter Some authors make special provisions when the rights to their works are sold that say the author has script approval of any adaptation that comes out (John Grisham does this, I believe, and Frank Miller scripts his own works and has directorial and editing approval as well)
Authors are generally more savvy about this now than they were 10 or 20 years ago, and obviously when an author's work is old enough to have become public domain all bets are off. But plenty of authors (cough, Dan Brown, cough) are more than happy to sell their story for multi-millions, and wash their hands of any responsibility to their fans.
As counterpoint to Frank Miller, look at Alan Moore, another graphic novel genius. He got so fed up with terrible terrible adaptations being made of his work (the comics publishers got to sell the rights to those) he finally said
"OK, fine, make whatever movies you like. Just don't use my name on them anywhere and split my share of the money between the artists, letterers, etc. that worked on the comic with me."
That's why V for Vendetta says "Based on the characters created by *artist" not "Based on the characters created by Alan Moore"
*Forgive me fellow comics geeks, the artist's name has slipped my mind.