Richard Matheson is the author of over twenty novels and something like four million short stories , nearly all of which have been made into films that bear little resembalance to the source material.
Richard Matheson's work has been adapted for both stage and screen, yet, as any snooty lit major will tell you, the books are always better. The best part is, he's written something for everyone.
For the person who fucking hates sparkly vampires: I Am Legend.
For the romantic who believes that love can transend time: Somewhere In Time (aka Bid Time Return)
For the person who thinks haunted houses aren't scary: Hell House
For the person who is already kinda scared of truckers: Duel (yes, that Duel, the one that Spielberg made in the '70's).
For the Sci-Fi fan who wants a giant spider that makes Shelob look like a pussy: The Incredible Shrinking Man.
His books are straightforward, lacking overly elaborate wordplay or unnecessary verbage (in other words, he cuts to the chase). They are also wildly imaginative, thought-provoking and (when he wants them to be) scary as hell.
Remember that Star Trek where the transporter malfunctioned and Kirk got split into "good Kirk" and "evil Kirk?" - Matheson.
Remember that Twilight Zone where the creepy guy offers the couple a shitload of money to push a button that will kill some random person? - Matheson.
Remember that TV movie (Trilogy of Terror) where the little Zuni warrior doll chase Karen Black all over her apartment? - Matheson
Remember Kolchak: The Night Stalker? - Matheson
Remember that "Amazing Stories" episode with the interstellar beauty pagent? No? You know, the one where Weird Al Yankovic played an alien with a cabbage for a head? Still nothing? Well, fuck it, Matheson wrote that, too.
In addition to writing for Corman as mentioned above (forgot already, didn't you?), Matheson also wrote The Devil Rides Out for Hammer Studios. It is widely considered to be the finest film ever made by Hammer.
His novels Hell House, I Am Legend, The Incredible Shrinking Man, A Stir of Echoes, What Dreams May Come, Somewhere In Time, Someone is Bleeding, Ride the Nightmare and The Beardless Warriors have all been turned into films, with I Am Legend having been filmed four times (and they still haven't gotten it right!). Often, his stories are changed drastically on their way to the screen, so if you hated the movie, give the book a shot, you might like it.
His short stories, "Button, Button," (filmed as The Box), "Real Steel," "Blood Son," "The Last Rites of Richard Keene" "Dying Room Only," "Duel" and "Being" have all been made into feature films.
Oh, and he also wrote Jaws 3-D, but, hey, we all fuck up sometimes.