It was an autobiographical work written by Stern, though I've only read snippets from the book, so I couldn't tell you that much about it.
The movie itself was executed pretty well, though it didn't live up to the promotional hype put out by "The King of all Media."
Read the book & saw the movie...agree with you re not living up to the hype. Used to enjoy the show, but it went downhill (or I went uphill ;-) over the last ~ 10 years & when he went off on Pres. Bush, that was the last straw.