The shoeless craze captivated the marathon crowd first, with books promoting barefoot running and even "shoes" that fit the foot -- toes and all -- like a glove.

And now, the trend is stepping into the land of the rest of us -- the walking crowd.

Pedestrians are shunning things with heels and curvaceous inner soles and stiff leather sides. Instead, they want something to protect the foot and keep it warm, and that's about it.

"As we continue to see the casualization of America grow and grow and grow, it has reached the footwear business to the degree of, 'How much more casual can you get than running shoes?'" said Marshal Cohen, chief industry analyst with the NPD Group, a market research firm. "Here's your answer: unstructured footwear that is as cozy as wearing nothing on your feet."

In shades of brown, with fringes or not, moccasins have returned as around-town -- as opposed to just padding-around-the-house -- footwear. Toms Shoes, with ads blanketing the country, sells footwear that exhibits only slightly more textile gravitas than ballet slippers. Ballet slippers, too, remain fashionable, as well as "driving" shoes, moccasin-like footwear with a little tread on the bottom.

The California company Sanuk goes out of its way to distance itself from things that swaddle, constrict and support.

"THESE ARE NOT SHOES" proclaims Sanuk hang tags. "Unlike stiff shoes, our patented sandal construction allows your feet to bend and flex the way nature intended."

The Sanuk brand came about after company founder Jeff Kelley ran up a long pair of steps twice in one day -- once barefoot, and once with shoes. The barefoot experience, he noticed, felt more natural and healthy.

He built a shoe that he felt would simulate going barefoot, manufactured it, and believes the approach is the future of shoes.

"There is barely any support," he said. "We are trying to educate you. When you have support in there, it might feel good, but you will become dependent on that kind of support. The best way to walk around is barefoot. We try to build shoes that are closer to a barefoot motion, thus improving your feet."

Podiatrists aren't thrilled with this celebration of shoelessness. People wear shoes, they say, because in modern society they need them.

Few people have an ideal foot type that doesn't require support, said Dr. Brett Sachs, a Colorado podiatrist. "Most people I see are ones who have flat feet or high arches or are getting other types of symptoms related to the fact they don't have the support their feet should provide them, and stress is getting redistributed to other parts of the body."

Barefoot advocates say going shoeless makes them feel more powerful, but Dr. Clinton Holland, another Colorado podiatrist, doesn't buy it.

"The whole idea of strengthening your feet by not wearing shoes, there's nothing that backs that up," he said.

But he's not opposed to shrinking from support.

"I tell patients, if it helps you, do it," he says. "If it feels better, then knock yourself out."

On a recent chilly afternoon at a Denver-area pedestrian mall, walkers wore a variety of support-free shoes, including Sanuks. Moccasins, too, were on parade.

"It's kind of like wearing slippers, but more appropriate for going out," said Sarah Grimsdale, 20, in brown Minnetonka moccasins, made by the Minneapolis company. "It's like a thick sock."

Grimsdale never wore moccasins until about a year ago, when she decided to follow her friends into the world of support-free footwear. Now, she's sold.

Her friend Elissa Tuck, 20, said she always wears moccasins -- hers were ankle-length, fringed and made by Steve Madden -- because of "the natural comfort."

"They allow for regular movement," she said. "It really is like you are not wearing shoes."