On July 14, a season ahead of schedule, Doubleday will flood bookstores with copies of The Accidental Billionaires, Ben Mezrich's exposé on the social-networking giant Facebook. Hype around the book has been building since well before the 40-year-old Back Bay bon vivant started writing in earnest. Last spring, after Mezrich scored a $1.9 million advance for the project—and promptly sold the film rights to Scott Rudin, who has The West Wing creator Aaron Sorkin already at work on the script—a copy of the proposal he'd circulated leaked to the tech blog Valleywag. "This is the exclusive, true story that you won't read anywhere else," Mezrich wrote in the proposal, which contained all the author's familiar tropes: Sex! Money! Genius! Betrayal! (Indeed, each of those words appears in the book's subtitle.) In one scene in the proposal, the girlfriend of Facebook cofounder Eduardo Saverin sets his dorm room on fire in a jealous rage after learning he's been cavorting with a Victoria's Secret model. Another vignette, set in 2004, depicts Saverin and Facebook founder Mark Zuckerberg feasting on koala meat on a yacht owned by the CEO of Sun Microsystems.

Notwithstanding those salacious details, the bigger intrigue has centered on Mezrich himself. Since his 2002 page-turner, Bringing Down the House, about a group of MIT geeks who win a small fortune counting cards in Las Vegas, he has cornered the market on tales of overeducated world-beaters. That book, the former novelist's first foray into reporting, spent over a year on the New York Times nonfiction bestseller list. It was followed by three more with similar plot lines. All were sold as remarkable "true stories."

In fact, as we now know, Mezrich gives readers "truthy." Last year, as Bringing Down the House hit theaters as Kevin Spacey's 21, Mezrich copped to rearranging details and creating composite characters for the book, stirring a controversy he dismisses with a touch of annoyance. "There are different forms of nonfiction. My books are nonfiction," he says. Mezrich writes fast-paced romps that sell by the pallet, and if the literary world is semantically ill equipped to categorize his oeuvre, well, that's not his problem. Or at least, it hasn't been so far.

With The Accidental Billionaires, Mezrich is for the first time dealing with readily fact-checkable material, in a story about a big, ballyhooed company. Tackling Facebook's creation, in other words, is a big step up from chronicling anonymous MIT card counters. Since he's covering a topic that's already been picked over by packs of journalists, he won't hook readers by rehashing old reporting; the challenge he sets for himself is in revealing new truths—a tall order with Facebook, which has always kept a buttoned-up profile while battling a slew of lawsuits. Indeed, attorneys for Zuckerberg and his many foes have spent years in court sweating the kinds of details Mezrich usually likes to gloss over or embellish.

Not surprisingly, within seven hours of the book proposal's hitting the Web last May, a tech journalist cried foul, pointing out that Scott McNealy, the CEO of Sun in 2004, has never owned a yacht, and therefore could not have hosted a floating bush-meat party. "It exploded before I had gotten deep into the book," Mezrich says of the criticism, pointing out that the final product is different from his pitch to publishers. But The Accidental Billionaires, a very rare review copy of which Boston has read, bears a strong resemblance to the proposal Mezrich sold. The koala is still there, though the meal now takes place on the yacht of "one of the original founders of Sun Microsystems." (Incidentally, each of the four founders of Sun has denied owning a yacht in 2004; the one who has since taken up sailing happens to be a vegetarian. The scene is completely false, say sources close to Facebook.) What's more, in the book it's Zuckerberg, not Saverin, who scores the unidentified lingerie model. "Some of the writing about Mark Zuckerberg and the creation of Facebook is more accurate than others," says Elliot Schrage, the company's vice president of communications. "This book appears to fall in the 'others' category. We think future efforts will tell a better and more accurate story."

To cover himself, Mezrich opens The Accidental Billionaires with a 285-word author's note that reads like a mea maxima culpa, admitting he's again fudged facts to fit his idea of a good yarn. But to him, this wanton juking of details, dialogue, and chronology doesn't make his chronicle of Facebook any less credible. "What's in my author's note doesn't mean the book isn't nonfiction," he says. "It's a true story."

Actually, the back cover of The Accidental Billionaires bills it as an "incredible" true story. In shoehorning the tale into his narrative formula, though, Mezrich stops well short of providing the definitive book on Facebook. Such a book would flesh out the intelligent, dynamic characters—all flawed in interesting ways—who built this billion-dollar social network. Such a book would explore the mysteries that lie at the heart of the company's founding and would at least try to answer the Big Question: Is Mark Zuckerberg a genius, a thief—or a bit of both? That's a hard book to write, and rather than untangle any still-unresolved controversies, Mezrich mostly steers clear of them and heads into the familiar waters of libidinous hijinks. The result is a book that doesn't live up to its billing: It's not all that true, and not all that incredible. This time, Mezrich's primary sin as author isn't that he's larded his sexed-up story line with half-truths or pure fancy. It's that he largely ignores the stuff that would have made for an actual thriller.

Mark Zuckerberg's rise to business titan began in 2003, when the then Harvard sophomore designed "Facemash," a computer program that let users rank the attractiveness of undergrads by comparing photos that Zuckerberg downloaded from the school's servers (an act Mezrich hyperbolically portrays as legend-caliber hacking). Zuckerberg's exploits got him into trouble, but they also attracted attention. Fellow students Tyler and Cameron Winklevoss, twin rowers who would compete for the United States in the 2008 Olympics, had been working on an online social network for about a year with their friend Divya Narendra, a polymath from Queens. They needed a good programmer to finish the site, which would eventually be called ConnectU. In November 2003, they contacted Zuckerberg, who agreed to help the budding entrepreneurs.
But Zuckerberg never completed the work, and instead launched Facebook on February 4, 2004. The Winklevosses and Narendra soon sent a cease-and-desist letter; they later filed suit alleging Zuckerberg had ripped them off. Zuckerberg has always maintained his innocence, claiming he got tired of working on ConnectU's balky code, and that his new site was a natural evolution of Facemash.

This defense is one that Mezrich appears to buy, and one that supplies an easy story line: Zuckerberg, rejected by a girl, invents Facemash to compare and rate student photos (according to the review copy of the book, it's all women; in reality, it was both genders), which morphs into the picture-hosting Facebook. Mezrich posits that a desire for sex explains the creation of the site. "The impetus of everything in college, I think, is to get laid," he says now. "I know that was my whole purpose in becoming a writer. I think that in general that's why everybody does everything."

While letting his randy fantasies run wild, Mezrich neglects the legal drama that still pits Zuckerberg against ConnectU in a battle over Facebook's genesis. It's rich material: Early Facebook computer drives mysteriously vanished only to later resurface, with ConnectU attorneys speculating that several of them had been tampered with. Meanwhile, Facebook alleged that ConnectU waged a hacking attack on Facebook to swipe proprietary data. Just last year, it came to light in court that a forensic data expert had uncovered new files that ConnectU considers "smoking gun" evidence of Zuckerberg's alleged betrayal. At that point, Facebook had already settled its dispute with ConnectU for $65 million in cash and stock. The ConnectU founders are now appealing a ruling that enforces the settlement.

Ignoring all that, Mezrich hangs his own made-for-cable narrative on Zuckerberg's relationship with Saverin, a buddy who thought the secret to higher status (and more women) was gaining entry to Harvard's semisecret finals club scene. Saverin was the first partner Zuckerberg recruited to grow Facebook, and because Mezrich never spoke with Zuckerberg, he was left to build a protagonist out of Saverin. But Saverin is hardly an unbiased observer—he, too, has had a long-standing dispute with Zuckerberg. The origins of their feud date to Facebook's early days, when Saverin put up $29,000 of his own money as seed capital and tried to position himself as the business face of the company. He began to feel he was being used by Zuckerberg and undermined by Sean Parker, a Napster cofounder who was squiring Zuckerberg to venture capital meetings in California. At one point, Saverin froze Facebook's bank account in retaliation. The company ejected him from its management team on October 31, 2004, then sued him for trying to derail the business and allegedly leaking trade secrets. Saverin countersued. It was apparently while embroiled in this litigation that he was introduced to Mezrich, and the idea for a wild tell-all was born.

Last August, as Mezrich was working on the book, Zuckerberg resolved his legal differences with Saverin, who has since been restored to the Facebook organizational chart as a cofounder. If that was a bid to silence Saverin, it seems to have worked: A person familiar with Mezrich's reporting claims Saverin had stopped speaking with the author by last fall. (Mezrich himself refuses to discuss who his sources were.) Indeed, the book reads as if Saverin didn't fully cooperate with Mezrich. The big moment when he blocks the Facebook bank account is presented as an imagined scene. "I think Eduardo definitely was involved in a whole legal thing going on with Facebook, [impacting] what he could talk about and what he doesn't want to talk about," Mezrich says now.

What Mezrich unwittingly gets right is that Saverin was used. He was a checkbook for Zuckerberg in Facebook's cash-strapped infancy. Saverin didn't come up with the concept. He couldn't write code. He was largely a bench player whose main role in the company was a failed attempt to drum up some advertising. But that just makes him an even more dubious source on which to build an account of Facebook's meteoric rise.

While it's possible that Mezrich interviewed dozens of other people—in the book, he claims hundreds of sources—their contributions aren't apparent. To keep the action moving, he reduces most of his characters to caricatures. Some fare better than others. Tyler Winklevoss is cast as a food-throwing lug. Divya Narendra, who for cultural reasons has never touched a drop of alcohol in real life, is poised to swill champagne in one scene. Zuckerberg himself remains distant, a robot in a fleece. How strange, then, to see this cipher getting freaky with a coed in a bathroom. Rendering Zuckerberg and Saverin as campus studs, Mezrich shows them turning out groupies in adjacent stalls. But as much he wants you to believe that Zuckerberg—who's been dating the same girl since the site's early days—created his social network to score ladies, he provides no real evidence.

Take the episode in which Zuckerberg is reputedly picked up by a Victoria's Secret model at an underground nightclub, a scene that Mezrich sets in the summer after Facebook launched. It's hard to fathom how a Victoria's Secret model would be aware of the still-penniless startup in 2004, much less lust after its awkward kid founder. "I just told the story that I was told by multiple sources," Mezrich explains now. "More power to Mark if that's what really happened. ...I have a feeling that Mark Zuckerberg right now could date anybody he wants to. ...Mark has done some amazing things, and if having sex with a Victoria's Secret model is one of the things that he doesn't like to read about himself, I would be surprised."

Other flights of fancy are just baffling, as they don't even add anything to the story. Mezrich describes a Harvard commencement ceremony at which president Larry Summers is onstage handing out rolled diplomas from a bin. Mezrich, who went to Harvard himself, ought to know that's not what happens: Students are given their diplomas in their residence halls, where they're presented in crimson envelopes.

Mezrich's slapdashery becomes more troubling when it actually clouds the reader's understanding of Facebook. For instance, he writes that the Winklevoss twins, while in England in July 2004, met a barrister who told them of his daughter's experiences with Facebook as an exchange student at Amherst College. At that point, though, Facebook hadn't yet spread to Amherst, let alone across the Atlantic. And here's where facts matter. If a book purports to show how a fabulous idea became a $1 billion sensation overnight, a working knowledge of how and when that company took off isn't too much to ask for.

Most amazingly, for all its bravado, The Accidental Billionaires fails to address that most critical foundational event in Facebook lore: the creation of the site itself. The book skips right over Zuckerberg's quitting ConnectU and resumes the day Facebook launches. For some reason, the drama-loving Mezrich elides the most controversial episode in the company's history. No imagined scenes or re-created dialogue. Nothing about what Zuckerberg is alleged to have done or not done as he invented Facebook. Is this the one place where Mezrich (or the publisher's lawyers) realized he just couldn't venture? Either way, the omission feels like a fitting coda to the book itself.

With his $1.9 million to spend on research and his supposed myriad sources, Mezrich squandered a chance to break new ground. It appears he was never interested in even trying: Mezrich's book proposal, which was a scant 13 pages long, made no mention of the ConnectU controversy, or the much-publicized allegations that Zuckerberg pilfered the idea for Facebook. A deeper accounting of events might have forced him to pick a side, which was never his goal. "I'm not a hatchet man. I don't go after anybody. That's not what I do," Mezrich says. "I tell fun stories about people doing amazing things."

Unfortunately, he's left a lot of this one untold.

Freelance writer and Harvard graduate LUKE O'BRIEN chronicled the rise of Facebook for 02138 magazine.