There’s a juicy sentence tucked away near the end of John Ortved’s preface to The Simpsons: An Uncensored, Unauthorized History, one that neatly describes the new book’s appeal for fans of the canonical, endlessly quoted, longest-running sitcom in TV history. In explaining why he structured his book as an oral history, compiled from both original interviews and excerpts from old ones, Ortved says that his approach is all the more logical because of “the lack of co-operation from Jim Brooks and the current Simpsons staff.”

The subtext in this line is clear: If you want to find the dirt they — for example, executive producer Brooks, creator Matt Groening, and the voices of the Simpsons themselves — don’t want you to know, you’ve come to the right place.

I’m not sure how well Ortved, a 29-year-old former Vanity Fair staffer, is able to follow through on this delicious subliminal promise, but his Uncensored, Unauthorized History is nonetheless a well-told patchwork that, despite the occasional lapse into editorializing, shines formidable light on the show that over the past 20 years has earned its parent network $3 billion in revenue, a Peabody Award, a star on the Walk of Fame, and 23 Emmys (though, curiously, never one for Outstanding Comedy Series).

The story begins when Groening, then a syndicated underground cartoonist, comes to the attention of Brooks, who commissions a series of 30-second interstitials to run as part of The Tracey Ullman Show. Before long, these quirky clips overshadowed the rest of the show, which is when the then-fledgling Fox Network took a risk the established networks wouldn’t: They put an expensive, adult-oriented cartoon in prime time.

Cue Bartmania. Cue in-fighting and “creative differences.” Cue a new benchmark for modern comedy.

As Ortved’s numerous citations make clear, a lot of this information is not new, and as a result it’s possible that bigger fans than myself (I put myself somewhere around the 65th percentile) may already know this trajectory, as well as the bulk of the underscoring anecdotes. But if nothing else, the oral history format allows for the timeline to really breathe, and presents shared experiences from multiple — and frequently conflicting — angles.

Consider the ongoing question of whether Groening deserves as much credit (and money) as he continues to receive for the show’s success. The general consensus in the book is no. But while many of the early staffers admit that Groening was a creative visionary and a more-than-affable boss, a particularly disgruntled assistant to executive producer Sam Simon claims to have despised the show’s creator so much she came up with a nickname for him: “Fat Fuck Groening.”

Ortved also devotes a substantial number of pages to the legendary writers’ room, where, for the first few seasons, a bunch of the funniest people in America sat around a table and cranked out dozens of classic scripts, one after another. These writers included current Late Night host Conan O’Brien — whom Ortved does interview firsthand — as well as George Meyer and John Swartzwelder, two senior writers who take on near-mythic status in the eyes of their peers and successors. For comedy nerds, these chapters are the real payoff.

Still, the book is not without flaws. Questions of censorship aside, the absence of fresh quotes from Groening and Brooks undoubtedly leaves a gap in the story. And Ortved’s between-quote narration has a bad habit of parachuting in the author’s opinions — particularly about the subjective world of comedy itself — without justification of any kind.

My biggest problem, though, is that it seems a little premature to attempt such a broad, all-encompassing retrospective. The Simpsons is still on the air, after all, and will remain that way until at least 2011. At the same time, many of the people Ortved interviews already speak of the show in the past tense — its glory days now nearly a decade behind it, and yet it keeps chugging along, slowly but surely, into irrelevance.