Shortly after I began writing this column, People Magazine started appearing in my office. I quickly noticed two things: first, my officemates snickered with superiority at the thought of a “media critic” deigning to read such an inconsequential bon-bon; second, as soon as I turned my back, the magazine disappeared. Soon I heard references in water cooler conversations to stories in that week’s issue.

Where else can you learn what effect studying the Kabbalah has had on Madonna’s marriage? Or that Michael Bolton baby-sat for Paula Abdul when she was young? Not to mention the startling news that minuscule sex therapist Dr. Ruth trained as a sniper, and can assemble a Sten gun blindfolded?

This week marks the thirtieth birthday of People. Time flies when you’re having fun. And People readers have a lot of fun. It’s a guilty pleasure — one reason why it’s become “the most successful magazine in history,” according to publisher Kathy Kayse. Consider these facts: average weekly circulation is in excess of 3.5 million — with nearly 1.5 million of those readers buying the magazine at the newsstand for full price. Counting pass-along readers such as my co-workers, People reaches an estimated 36 million adults each week — or one in five Americans.

Advertising figures are equally bullish, says Kayse. “We’ve been number one in revenue, ad pages and share of ad dollars for at least the past three years,” she says. “And we’re coming off a record year, with $744 million in gross revenue.” Kayse turned coy when asked to detail the magazine’s profits, but it’s a safe guess that it contributes the lion’s share — hundreds of million of dollars — to the bottom line of Time’s magazine division.

But it’s not all fun, money and silly celebrities at People. In fact, the extent to which People’s journalism excels is one of the profession’s dirty little secrets — Something that irks Managing Editor Larry Hackett. “You can face taunts if you’re seen reading People,” Hackett admits. “Particularly if you’re a man! And yes, our journalism gets short shrift — the accepted image is that of Jeff Goldblum in ‘The Big Chill.’”

But Hackett, who spent eight years at the Daily News, says People’s “rigor and resources are far more impressive than other places I have worked. We have a lot of journalistic firepower. I cannot tell you how many newsrooms use ‘People’ stories to fact check their own. I certainly did.” Hackett knows the “quick, common shorthand is that People is all fluff — but we are not, and we are not given enough credit from critics. Over the years, though, readers have come to trust us.”

Thirty years on, the People formula remains clear: stories of “extraordinary people doing ordinary things,” coupled with ordinary people doing extraordinary things. “It’s about life passages,” Hackett explains. “Life, death, marriage. The celebrities change, but the stories are the same.”

Take, for example, Princess Diana, who holds the record for appearances on People’s cover with fifty-two. (Julia Roberts is a distant second with eighteen.) “It’s a primal story,” says Hackett. “The beautiful princess, the prince, the evil mother-in- law. We try to humanize the larger-than-life.”

Speaking of which — where else can you learn whether Jessica Simpson wears thongs or briefs? People. People who read People. They’re the guiltiest people in the world.