I'd definitely agree with all who mentioned Stephen King. I've read most of his works and the one I found truly hard to read at night, but by the same token didn't want to put down, was, The Stand.
Again, as most of Kings books are, it stunk when translated to film.
Gerald's Game was indeed graphic, wasn't it? Another, that I have lost in a few moves and want a copy of again, is Rose Madder.
King has a wonderful way of weaving characters together in so many of his books. He is by far, my favorite horror author.