One of my favorite movies about writing and also a pretty good book. Yes I've seen the movie (and own it) and also read the book--and own it too.
Wonder Boys is about Grady, a writing professor at a Pittsburgh area college who is sleeping with a student and his dean, smokes weed, and is writing a novel that makes Infinite Jest seem like a pamphlet. The title of the novel he's writing is the title of the book itself, but there's also a double-meaning as a long time ago Grady was a "wonder boy" (or boy wonder) with a really successful novel he has struggled to top. He also has a talented novelist named James in his class; James is a future wonder boy Grady reluctantly tries to steer onto the right path. To add some urgency to the setting, Grady's agent comes into town to try to get a look at the book Grady is writing. Over a weekend Grady and James bond while getting attacked by a dog that James shoots, fleeing to Grady's in-laws for Passover, and facing their various demons.
They're both good but it's another where I'd say to watch the movie unless you really feel like spending the extra time on the book. The movie strips out some of the bloat about the book, specifically the Passover seder that goes on much, much too long in the book. The seder thing isn't really important to the overall story, so taking it out of the movie made sense. Though this was a case of Hollywood whitewashing because in the book Grady's in-laws are Jewish and Asian.
I mentioned when I reviewed Ant-Man that everyone who stars in this movie has appeared in a superhero movie: Michael Douglas in Ant-Man, Tobey Maguire in Spider-Man 1-3, Robert Downey Jr in all those Marvel movies, Frances McDormand in Darkman, and Katie Holmes in Batman Begins. I don't know if there's anything significant about that or not. But I do really like the movie. The book is longer, and a little more depressing, but it's also worth a look.