THE WOMAN'S SHOE: An external covering for the foot? Or a peek into the inner workings of her soul? Sole mates.

One thing is certain. American women spent $17 billion on fashion footwear between October 2004 and October 2005, according to retail and consumer-information firm NPD Group.

Now, the NPD Group didn't emphasize that shocking stat with capital letters. But if it had, it would have looked like this: 17 BILLION DOLLARS.

That's the amount of Bulgaria's foreign debt. It's the amount China will spend on six new hydroelectric power plants on the Yangtze River. It's the price New York City is expected to pay if it ever resurrects the Second Avenue subway, a pipe dream that's been in the offing since 1920.

So. The woman's shoe. External foot covering? Or unhealthy obsession?

"Definitely there's a level of obsession there, for sure," says Chris Silverman, 35, who owns 22 Shoes in Oakland's Rockridge neighborhood along with his wife, Alexandra. "It's just one of those things. Some people stress about finding the perfect-fitting jean. They want their butt to look a certain way. It's the same way, but worse, with shoes. Women will search the ends of the earth for a pointy toe and a kitten heel with a little pink in it. It's an endless quest for the perfect shoe."

Shoes, shoes, everywhere

There's no denying the shoe's place in popular culture. They inspire film, most recently in the Cameron Diaz and Toni Collette vehicle, "In Her Shoes."

They inspire television, most memorably when Sarah Jessica Parker cooed "Hello, lover" to a pair of Christian Louboutin sandals in a window during an episode of "Sex and the City."

They inspire movie stars, most greenly when Natalie Portman pointed out at the Golden Globes that her shoes were vegan.

And they inspire world events, most politically in 1987 when Imelda Marcos' collection of

1,220 pairs came to symbolize the extravagance of her husband Ferdinand's rule and the couple's life of luxury amid the overwhelming poverty of the Philippines.

"I did see shoes among many other things in Malacanang Palace just after they fled," says Seth Mydans, the New York Times writer who covered the fall of Ferdinand Marcos, via e-mail. "I don't know if I saw all of them. They were extravagant like everything else there. The word that's used to describe her flamboyance is 'Imeldific.'"

The most recent evidence pointing to the power of the woman's shoe comes from the book-turned-film "The Devil Wears Prada," which is currently in production and stars Anne Hathaway and Meryl Streep. The movie poster features a solitary red stiletto with the three tines of a pitchfork as the heel.

No doubt about it, shoes sell.

"The thing about shoes that's so captivating is that they're your one connection to the ground. They're a blend of form and function. They're a sculptural piece of art, and yet, you wear them," says Meghan Cleary, author of the newly published "The Perfect Fit: What Your Shoes Say About You" (Chronicle Books; $12.95). "Shoes can define your mood, your look, how people perceive you."

Overwhelmingly, the shoe obsession is a women's thing. Though Cleary thinks "men are sort of secretly obsessed with shoes," it's undeniable that shoes — whether they be slides, mules, kitten heels, pumps, or even sneakers — stir a passion in women.

"Men can be into shoes, but they're more linear in their obsession," says Cleary. "They might have two or three they obsess over while women might have your stiletto, your sandal, your beach sandal. It goes by mood. The passion level can be the same, but it's manifested differently."

The psychology behind women and their shoes is no joke. Honest-to-goodness cerebral thinkers have written books on the subject, like Susan B. Kaiser, who penned "The Social Psychology of Clothing." "Shoes," writes Kaiser, "embody the intersections among gender, class, sexuality, ethnicity, race, age, and the multiple joys, sorrows, ambivalences and anxieties of everyday life."

If that's too cerebral, then subscribe to the Cleary theory: "If you're in a really bad mood and need to change it around, then you might pick your red stilettos instead of your come-kick-me clogs. Feet themselves encompass so many nerve endings that resonate throughout the body, that how you feel in them can really determine how you feel."

Stats don't lie

Research backs Cleary's

A survey commissioned by Mervyn's department store on women's shoe shopping habits revealed that 58 percent feel that wearing a particular pair of shoes actually boosts their self-esteem.

And just as Ponce de Leon searched endlessly for the Fountain of Youth, women search endlessly for the Shoe of Esteem. At least, that's one explanation for why 40 percent of women buy three to five new pairs of shoes a year and more than one in four buy at least six pairs.

"How many pairs did I buy in the last year? Let's see," says Chanda Brewer of Oakland, a shoe dilettante. "One... two... three... four... um, 12?"

Brewer, 33, like many women, is attracted to shoes for three reasons: First, the foot doesn't have a bad day. If a woman's foot is a size 81/2 on one day, she'll still be an 81/2 on a day where maybe her favorite jeans feel a size too small. Second, the shoe shopping mirror doesn't show the entire body. And third, shoe shopping is just plain easy.

"It's a quicker purchase," says Brewer, who has 41 pairs that she wears regularly. "Unlike going to Nordstrom or something, I don't even have to talk to a sales person. They either fit or they don't. Whereas with clothes shopping, and the whole process of gathering them and putting them on, lots of times the clothes will look good on the rack, but not on.

Hey, babe, what's your shoe?

While the psychology behind women's love of shoes has been discussed over the years, what's been probed less thoroughly is what those shoes actually say about women. Though Cleary's book is as guilty a pleasure as a knee-high boot with a low heel, there's actually quite a keen insight to the different profiles of shoe wearers the author describes.

Calling the shoe's premise "shoestrology," Cleary breaks down women's personalities into three basic categories: Down-To-Earth, On-the-Go and Towering Heights.

Beneath those umbrellas are 30 specific shoe types, ranging from flip-flop girl to pointy toe skimmer girl to clunky chunky-heel loafer girl to, of course, stiletto girl. Each chapter has an overview of the girl — flip-flop girl is energetic, tanned and loyal, among other things, while designer bowling shoe girl is "scrappy and resourceful and roots for the underdog." Filling out the chapters are career and wardrobe advice and how each different shoe personality can invoke her "inner stiletto."

You really can find out more about yourself through your shoes," says Cleary, who's a half-ballet flat girl and half-stiletto girl. "Everyone is shocked at how accurate I am."

While shoes can say a lot about a person, sometimes what they say isn't necessarily a good thing. And sometimes, shoes get women in trouble.

Brewer, the Oakland woman with 41 pairs of shoes, says her shoe buying habits have caused arguments in the household.

"My husband does the finances and he looks online at our account — sometimes he knows I spent money before I even get home. It's a little scary," says Brewer. "He thinks I have a ridiculous amount of shoes. I'm trying to tell him that if you were to going to poll all different economic backgrounds, I'd be on the low end. He seems to think I'm on the high end. He just thinks it's outrageous."

The woman with the lock on outrageous, though, is Mrs. Marcos. Of the 1,220 pairs of shoes that were confiscated from Malacanang Palace, 220 are on display in a shoe museum inaugurated in 2001 by the sole diva herself.

Even Marcos says those shoes say a lot about her — or don't say, as the case may be.

"The shoes are my best defense," Marcos explained in an interview after her shoe display opened, "because when they went to my closet to look for skeletons, they found no skeletons. They found shoes."

You can e-mail Candace Murphy at cmurphy@angnewspapers.com or call (925) 416-4814.