It would have been difficult for the new ESPN tell-all book, Those Guys Have All the Fun, to live up to the wild hype that heralded its release. The hardcover doorstop, nearly 800 pages, was so guarded by publisher Little, Brown that advanced review copies weren’t sent out. Instead, journalists interested in writing about the book had to come to the publisher’s offices, sign an NDA, and spend the day reading it there, no note-taking allowed.

The strategy worked — rumors bounced around media circles and beyond that the book was going to be extremely juicy, full of behind-the-scenes shockers from the world’s biggest sports empire. But folks hoping for jaw-dropping secrets about the business in Bristol (as we were) may be disappointed; most of the sizzle comes from drama between the on-air personalities (readers of Deadspin will no doubt be completely satisfied). Anchor Chris Berman and “Pardon the Interruption” co-host Tony Kornheiser hate each other. “Sports Guy” Bill Simmons, ESPN’s best-known writer, resents his employer. Reporter Jim Gray was the brains behind the ill-advised LeBron egofest, “The Decision.” Erin Andrews was very shaken up by that voyeuristic video that hit the Web. These are hardly revelations, but nonetheless have fun gossip value.

Where the book shines is in the reporting. Those Guys Have All the Fun is an outstanding work of journalism. Easing interviewees into such comfort that they said what they did on record is an enormous achievement for Miller and Shales, who took on the same effort with their SNL book, Live From New York. This is indeed the definitive account of ESPN, if perhaps 300 pages longer than it needed to be.

The oral history format — authors briefly set the scene in italics before each source is heard from, one at a time — can grow tiresome, but there likely was no better way to present the recollections. The structure also on occasion sets up a compelling back-and-forth between sources.

In one of the best sections on the business side of things, Miller and Shales bring us back to 2005 when ESPN famously fumbled its broadcast deal with the NFL. ESPN had broadcast Sunday night games since 1987, and ABC (also owned by Disney) had always shown Monday Night Football (MNF). But Disney head Michael Eisner no longer wanted Monday night; it was losing too much money. It’s here that the multiple-voice narrative style functions at its best. We hear from every exec involved: Steve Bornstein, NFL negotiator formerly with ESPN and ABC; Dick Ebersol of NBC; and both Eisner and Bob Iger of Disney DIS , to name a few. To sum it up, Iger didn’t believe NBC was in the running for either night; he offered up an insulting $1.1 billion to get a package deal for both Sunday and Monday nights. Instead, the NFL gave Sunday nights to NBC as Iger and Eisner, now with egg on their faces, ended up grossly overpaying just to get MNF — with no playoff games. As sportscaster Al Michaels sums it up: “Major blown opportunity.”

Additional lesser-known moments are recalled along the way, such as ESPN’s hurried launch of ESPNews in 1996 as a direct response to CNN SI (Steve Bornstein apparently told people, “Just get the goddamn thing on the air. I want us to beat those sons of bitches.”) and Chris Myers recollecting his interview with O.J. Simpson on “Up Close” — the first Simpson did after his trials — thusly: “After the interview, he was sarcastic and said, ‘Well, it was great talking sports with you,’ since we never talked sports. I said, ‘What did you think we were going to do, talk about your Heisman Trophy?’” That’s good-to-the-last-drop banter.

At Fortune we love hard numbers, and Those Guys Have All the Fun is packed with them. Miller and Shales give all the stats, from the total number of distinct sports shown on ESPN (65), to the dollars of every U.S. monthly cable bill that, on average, go to ESPN ($4), to calendar dates that will at the very least make you realize, My god, Chris Berman has literally been on ESPN since he was a child.

This is a book that, though big and messy, delivers a hell of a narrative. Sports fans will be hooked right away, but ESPN newbies will stay for the story of how a once crazy idea (an entire channel just for sports?!) became a gargantuan business.