By SHARON COHEN,AP National Writer

The family sleeps in a single room, its walls bare and windowless, its cracked concrete floor crowded with plastic storage bins and three mattresses: one for dad, one for mom and daughter, one for the three young sons.

Fluorescent lights will flicker on at 6 a.m., to start their new day.

This room in an old red-brick factory-turned-shelter in Chicago is home for the Torres family. They consider themselves lucky to be here. They have a warm place to stay. They have three meals a day. And they have each other.

The family is among an estimated 500,000 to 700,000 people who, on any given night in America, lack a real home.

Homelessness exploded as a politically potent issue during the Reagan era of the 1980s, and according to some estimates, the numbers of those without a permanent place to live has doubled in the last 20 years. But some experts say more people now fall into that category only because billions of dollars have been spent to build shelters.

Americans are troubled by this issue: An Associated Press poll taken Feb. 11-13 found 53 percent consider homelessness a very serious problem, while 36 percent say it’s somewhat serious. Some 56 percent see the long-term homeless as victims of circumstances beyond their control, according to the survey. It was conducted by Ipsos-Public Affairs among 1,001 adults and had a sampling error of plus or minus 3 percentage points.

Who are the homeless? Where do they live? How did they come to this?

For a snapshot, AP reporters and photographers spent 24 hours earlier this month meeting with people who live on the streets and in shelters, following them to their jobs, watching them in court and talking with those who try to help them.

Here are some of their stories:

After midnight: Portland, Maine

Scotty Partridge is restless and pacing outside a blue tent pitched in the muddy soil among the barren spruce trees on the outskirts of Portland.

“Hobo Jungle” has been his home for nearly a year. The months have taken their toll: Partridge’s clothes are dirty and frayed. The skin of his windburned cheeks hangs loosely, like someone who has lost weight too quickly.

On this 35-degree night, most of Portland’s homeless are two miles away in the Oxford Street Shelter, sleeping on rows of mats four inches apart.

But Partridge prefers a tent he has furnished with plywood, a radio, a battery-operated television and a discarded propane heater. He has a cell phone, too – paid for by panhandling and collecting aluminum cans.

Partridge, 36, swigs a can of Milwaukee’s Best and reminisces about the days when he had a good job at a printing company in Chicago, a nice apartment, a woman he was going to marry.

But when the relationship soured in the early 1990s, he returned home to Maine and moved in with a friend who was using heroin. Partridge soon became hooked, too.

On methadone for five years, Partridge survives day to day.

“I can’t get up and go to work out of a tent,” he says. “I need a stable environment to get up and shave, shower, and clean, feel normal and go. When you’re in a tent, every day is so hard. … Your priorities are so whacked out. … You think about, OK, how am I going to eat today and how are my boots going to unthaw because they’re frozen solid? …

“I go and crawl into my tent and then it’s another day,” he says. “… Being homeless is a full-time job.”

8:30 A.M.: Chicago

A 10-degree wind chill whips through the North Side streets of Chicago as 6-year-old Angelina Torres, in her pink wool hat, and her twin, Angel, in his Spiderman gloves, make their way to kindergarten.

Their mom, Eileen Rivera, leads the way on the seven-block walk. Her two older sons, Omar, 9, and JJ, 10, have already left for another school – a bus picked them up at 8 a.m. at the Sylvia Center, the shelter where the family has lived for eight months.

Her arms folded against the cold, Rivera walks briskly, noting her twins have stayed in shelters about half their lives. “They just blend right in.” She pauses, then adds: “It’s sad.”

Her husband, Jesus Torres, recently found work operating a forklift, earning $7 an hour. The husky, outgoing father has been a handyman, pizza delivery man, ice cream cart driver, cashier and drug store clerk – sometimes working in exchange for welfare checks.

The Torreses are on waiting lists for public and subsidized housing.

Rivera tells her children this is just a steppingstone. “Guys,” she says, “we have to do this just a little longer. We have to go through this to get to the shining star.”

Rivera knows exactly what that will be: “Your own toilet. Your own tissues. Your own bath. Your own window. Things that are yours. Just yours.”

3 p.m.: West Virginia

A light snow falls in the mining town of Monongah, W.Va., as nurse’s aide Harleigh Marsh does a final check on his patients at St. Barbara’s Memorial Nursing Home. Finding a plastic baby doll atop a medical cart, he returns it to the waiting arms of a patient named Dora.

He leaves and by 3:15 p.m. arrives at Scott Place, a hillside shelter for the homeless in nearby Fairmont.

Marsh, a 48-year-old former sailor, is one of nearly 250,000 veterans who are homeless on any given night in America.

He lives in a dimly lit 14-by-14 room. A Zane Grey western and toiletries sit on his dresser top. He lost most of his family photos in his travels.

After leaving the military in 1979, Marsh tried college, but wanderlust returned. He worked as a drywall hanger and painter, renting rooms by the week, living from a suitcase.

In Milwaukee, he met a woman and fell in love. They had a son. Marsh was heartbroken when she found someone else – and almost overnight, he was homeless.

He ended up in Scott Place last year, struggling with depression. “But with the psychological help of the VA … and a lot of time to think, I just worked it out,” he says.

Marsh loves his job but after $300 monthly child support payments, he’s left with just $140 a week – not even enough to travel to Milwaukee to see his 13-year-old boy, William Ray.

They talk, but haven’t seen each other since August 2003. “It tears both of us apart,” he says.

This fall, Marsh plans to apply to nursing programs at two local universities. If accepted, he’ll work full time.

For now, he has a room, a pine bed, a comforter and a sense of peace.

“I have a place to go in the morning.”

Late evening: Las Vegas

A few blocks from downtown Las Vegas’ casinos, Clarence Woods is on his way to buy a pack of cigarettes.

A week ago, he lived on the streets. But work as a day laborer has allowed him to move into a $370-a-month hotel. He doesn’t know how long his luck will hold.

The 53-year-old Woods is a father of five but says he’s too embarrassed to tell his children where he’s living. He says he ended up homeless because he was irresponsible.

“It’s like hell,” he says, his cranberry stocking hat pulled snug over his ears in the desert chill. Woods says there aren’t places to help homeless people like him.

He once did well in Las Vegas and owned his own upholstery shop, he says. But he went bankrupt and ended up without a home.

He calls himself a recreational drug user, drinker and gambler.

“It’s a real trap,” he says, the neon signs flashing behind him, “but it’s what Las Vegas is all about.”

9 p.m.: Seattle (Midnight EST)

The lights are about to go out on another day at Seattle University where about 100 people live in a homeless camp on asphalt tennis courts.

“Tent City” is both a haven and a political statement – the homeless shouldn’t be hidden. Volunteers cook meals and students and faculty organize legal and health clinics for residents.

Among them are Russell Mace and Angela Cope. He says he once made a handsome living running his own catering and house-painting business in Texas, where he fell in love with Cope. But she returned to Seattle to try to reconcile with her two kids and their father.

Mace, 45, says he turned to the bottle for a time. Then he and Cope, 49, reunited. They lived in cheap hotels until their money ran out. Now a tent is home.

In recent months, Mace has lobbied city council members and state lawmakers on homeless issues. “I have a sense of pride, a sense of dignity, a sense of community here – and a sense of purpose,” he says.

But he hopes his homeless days are numbered. He’s trying to resurrect a Web site he had for handmade eye patches; he wears a silver-plated patch over his left eye, which he lost in a hunting accident years ago.

After the camp goes dark, Cope shaves her partner, next to the only bulb still aglow at the front desk.

“We gonna get any coffee or are we going to bed?” Mace asks.

“Go to bed,” she replies.

They walk into the darkness, his arm around her back.

On the other coast of America, midnight has just passed and another day for the homeless has just begun.