BY JAMES PONIEWOZIK
So here's my theory. In a certain corner office at Esquire magazine, if you swivel the complimentary Propecia note pad on the leather desk set, a bookcase slides over, revealing a secret door. Behind that door is a winding passageway, with crackly pinups of Farrah Fawcett and Muhammad Ali taped to the walls. And the passageway leads to a tiny, humid room with leaky steam pipes and a bare light bulb swinging from a cord and a glass fire box on the wall, bearing an inscription that reads something like this: IF CIRCULATION DROPS BELOW X, BREAK GLASS.

It's just a theory. But if I'm right, that little glass panel is now shattered, the box emptied and the contents -- a cover of Pamela Anderson squeezing her bosoms together, the headline "Breasts!" and a salute to "The Triumph of Cleavage Culture" -- are available today for purchase on your newsstand. It is at least the best explanation I can come up with for this seeming self-parody, save perhaps to eradicate memory of the much-guffawed-over "Cocktail Culture" cover of 1997 (proving that, pace the old journalistic maxim, it no longer takes three examples to make a trend, just two Cs). Welcome to Cleavage Culture; your D-cup is ready.

Esquire is either America's worst great magazine or its best bad magazine, swinging harder, whiffing more grandly and occasionally connecting more dramatically than its peers. And the funny thing is, for several months running, Esquire's covers have been noteworthy and risk-taking for precisely the opposite reason of the bodacious current one. Bravely for a men's magazine, they featured unsexy men. Stack 'em up: January -- a bloodied Jerry Springer. December -- an ashen Bill Murray. November -- a creepy Fred Rogers. October -- a cracked bald head on the "What Did You Do After the Crash, Daddy?" cover. Despite its aging-Lothario rep, Esquire was looking far edgier than competitors like GQ, fronted by deadly dull objets of perfection month after month, or Details with its Tiger Beat for grown-ups pinups. It's as if Pam's mighty rack erupted unconsciously in furious reaction, an angry blast of magma and silicone heaved up by the hornier angels of Esquire's nature.

There is an editorial conceit justifying Esquire's package. Breasts, you see, are uniquely visible in our culture today ("Everywhere you look: tits"). In movies, on television, in magazines -- sometimes two to a customer! As you can imagine, this would be a difficult proposition to prove at any juncture in history, but Mim Udovitch -- an excellent writer who deserves the fat check just for biting her lip for this exercise -- provides the whatever the female equivalent of a beard is for the issue with an essay tracing the American breast from the falsies of the '50s ("an all-around culture of concealment that necessitated a breast that repressed and returned simultaneously") to the Wonderbras of today ("a falsie culture"). Comedian Sarah Silverman reveals that she has 'em; Thomas Kelly counters that men like 'em.

Whatever its philosophical pretensions, the Cleavage Culture issue just happens to come along at the heart of winter, when men's magazines compete to heat up their readership with V-for-Valentine's Day dicolletage. And it's a rare month indeed when Maxim finds itself out-cleft: With Esquire boasting Anderson, with GQ sporting CAD-designed Sports Illustrated swimsuit issue cover girl Heidi Klum and with Gear's Model Issue hosting Adriana Sklenarikova, eyes wide and blank, lips parted and hair in a bedroom muss like a just-deployed sex toy, Maxim inexplicably has Bridget Fonda -- a lovely lady who notoriously needed padding to fill out her bikini top in "Jackie Brown" -- to tout its "Lingerie Runway" feature (and even there it's aced by Details, which dedicates its entire issue to lingerie).

Winter is a conservative season. You hanker for the same Christmas turkey or Sunday pot roast; you spend the same 18 hours on the couch Super Sunday; and you curl up with the same familiar ta-tas on the cover of your waistcoats 'n' whiskey guide. The men's magazines, in other words, are basically serving visual comfort food. And these are old-fashioned meatloaves indeed, looking all the more dated when the rest of the industry has long since moved beyond the two-squeezed-together-glands template that has more or less been the default since the rise of mammals. We now have, for instance, Boobs-on-a-Plate, which came strongly into vogue last year (model leans forward, breasts lie supported by a plane or the front of her dress like fresh mozzarellas); the Boob Runway (breasts taped to the inside of the model's top, exposing what is not really cleavage but really more like a flesh landing strip); the Five-Finger Brassiere (breasts cupped by either the model's or a third party's hands); even PoMo-Nostalgia Boobs (Anderson, again, copping a Fawcett pose on the cover of Details last fall).

Indeed, more interesting than the subtle-as-a-mousetrap baits of men's magazines are the myriad uses of cover cleavage in other magazine genres. The great mystery of the newsstand, to the male reader, is that women's magazines make men look like pikers, using caverns and canyons of flesh to communicate class and demographic differences with a vocabulary nuanced enough to stump the 17th century French court. For Cosmopolitan, cleavage has long symbolized its trademark full-bore sexuality, and the January cover is a textbook example: This is cleavage with shadows inside it, cleavage with an X, Y and Z axis, cleavage so deep you can practically read the tag on the back of the model's dress. Whereas Mirabella (January), which aspires to be the women's mags' intellectual leader (sic), is so good-girl that it puts Angelina Jolie in a turtleneck. Meanwhile, issue after issue of fashion glossy W melds the two approaches -- relatively small-breasted models exposed in Boob-Runway mode down to the navel -- to connote classy edginess. Shoshanna Lonstein's noble efforts aside, we still haven't shed our Audrey Hepburn vs. Marilyn Monroe complex: Full sweater equals naughty girl.

The motif has been picked up, with a twist, by women's sports and fitness publications; Self, Shape and the like (with the notable exception, so far, of the outstanding recent startup Women Outside) so aggressively push Lycra-bolstered pontoonage you wonder if they cover any exercise below the ribcage. On the Jan./Feb. Condé Nast Women's Sports & Fitness, Krista Cassidy heavingly "(takes) time out from snowboarding to soak up some southern exposure" in the balmy waters of Mexico. So why not just show her, oh, I don't know, snowboarding? Because nothing says, "I may be athletic but I'm still a heterosexual woman" like cleavage! You can shoot skeet, these covers tell us, and fry it up in a pan; you can ride a mountain bike and still land yourself a man. Just mind you don't knock yourself unconscious with those things, hon.

And what's breast meat for the goose has quickly been ganderized by the decade's hottest magazine genre. That's right: Male cleavage is where it's at in men's fitness, further complicating the sexual confusion of the booming pecs-and-sex journals, whose black-and-white models have developed such gigantic and cleft torsos, flexed and thrust out on each month's cover, as to rival the lad mags' hood ornaments -- and have reaped a sizable cut of the traditional men's audience for it.

In the shadow of these buff cover stars, Pam Anderson's robotically squeezed bounty is a tumbleweed-strewn valley of death. With their mammary stock-in-trade replicated across the newsstand, men's magazines have no way to make breasts breastier, and less of a clue than ever how to grab the attention of a male readership that just wants to move up a cup size. That may be the reason, in fact, that below-the-waist peekaboos are starting to steal the breast's thunder: recall Gear's oh-so-classy layout of Peta Wilson on the can last year; notice GQ's Klum shimmying the straps of her slight bikini bottom well below her waistline. Cleavage may never go out of fashion, but as these masculinity bibles remind us, it helps to accessorize. For men's magazine editors, standing desperate atop their too-often-summitted peaks, there may be nowhere to go but down.