Michael Douglas plays Grady Tripp, a writing professor who suffers under the shadow of early success and fame from his first novel. In the years since he was the wonder boy of the literary world, he has unwittingly embraced his failure to live up to the astronomical expectations everyone had (and still has) for him. Rather than finish his second novel, he continues to write it, reaching close to 3,000 single-spaced pages before a pivotal scene in the film where it all blows away into the Ohio River - an image more frightening than a 1000 horror films to any writer. His current wife leaves him, his mistress (also his boss's wife) tells him she's pregnant, his editor (Robert Downey, Jr.) comes to snoop on his progress on the book and a slightly strange wunderkind student (Tobey McGuire) causes him an incredible amount of grief.
To label Douglas a boy is a bit of a stretch, even if you consider that his first book was published 7 years prior to the beginning of the movie; it would put him just north of middle age when success hit. The character in the book by Michael Chabon was much younger. But once you get over that obstacle (at least Frances McDormand, who plays his mistress, is more age appropriate than most movie girlfriends); the movie unfolds into a fascinating character study that hinges on Douglas being at his best, which he is.
Also, where else will you get to see Spider-Man and Iron Man hook up?