Kirkpatrick said that though Saverin and Zuckerberg were friends at Harvard and did start Facebook together, to his knowledge, Saverin was ambivalent about the project and didn't really understand Zuckerberg's vision.
When Zuckerberg and co-founder Dustin Moskovitz and others moved to Silicon Valley to pursue Facebook, Saverin stayed behind in New York, Kirkpatrick pointed out. That he would be able to provide Mezrich with full details about the company's growth is unlikely, given that he was absent for much of it.
Sarah Lacy, a longtime Silicon Valley reporter and author of "Once You're Lucky, Twice You're Good," first interviewed Zuckerberg when he was 19-years-old. Although she hasn't read Mezrich's book, given the lack of input from Zuckerberg, she questions the book's accuracy and balance.
"He has a very subtle personality, he's very shy and hard to get to know," she said about Zuckerberg. "There's an impish side to him that people read wrong."
Even those who spend a great deal of time with him misinterpret his motivations and actions, she said.
That Mezrich could get inside his head through the observations of others is unlikely. That the book implies that his motivation in building Facebook was to meet girls is dead wrong, Lacy said. Lacy and others said that from the beginning of Facebook, they have known Zuckerberg to be in a serious relationship with one woman.
"From the beginning, what fascinated him about Facebook was having the sheer efficiency. … Taking all that complex data and making it, within seconds, work for you," she said, pointing to Facebook's newsfeed as an example of that efficiency.
She also said that from her years covering startups she's observed that when emotions run high and founders part ways, the one left out -- in this case Savarin -- perceives the situation in a completely warped way.
Considering the amount of emotion invested in startups, she said, "everyone is going to have a totally different take on it."
For its part, Facebook, like its CEO, is distancing itself from the book.
"Ben Mezrich clearly aspires to be the Jackie Collins or Danielle Steele of Silicon Valley. In fact his own publisher put it best, 'The book isn't reportage. It's big juicy fun.' We particularly agree with the first part of that and think any readers will concur," said Elliot Schrage, a spokesman for Facebook.
But still, that Jackie Collins-esque drama works well for Hollywood flicks and, even though the book has yet to drop, a movie is already in the works.
In an Amazon review for the book, actor and producer Kevin Spacey, who first met Mezrich when he produced and starred in "21," an adaptation of "Bringing Down the House," announced that "Hollywood has come calling again."
"The Accidental Billionaires is the perfect pairing of author and subject. It's pure summer fun -- a juicy, fast-paced, unputdownable Mezrich tale that adds to his canon of lad lit," Spacy wrote.
Steven Elzer, senior vice president of media relations for Sony Pictures Entertainment, confirmed that they are developing a movie about the creation of Facebook, adding that Aaron Sorkin is writing the script and Michael De Luca, Scott Rudin, Dana Brunetti and Kevin Spacey will produce.