Every day, when the main library opens, John Banks is waiting to get inside. He finds a spot and stays until closing time. Then his wheelchair takes him back to the bus terminal where he spends his nights.

Like many homeless public library patrons, all Banks wants is a clean, safe place to sit in peace. He doesn't want to talk to anyone. He doesn't want anyone to talk to him. But the day he decides he wants help, he knows what to do: ask for the social worker.

The main branch of the San Francisco Public Library, where hundreds of homeless people spend every day, is the first in the country to keep a full-time social worker on hand, according to the American Library Association.

But cities across the country are trying different approaches to deal with patrons who use bathroom sinks as showers or toilet stalls as drug dens. In Philadelphia and San Francisco, libraries have hired homeless patrons to work as bathroom attendants who guide others to drop-in centers or churches where they can bathe.

In Portland, Ore. the downtown library is trying a penalty system for patrons who commit infractions _ banishing them from the library for a day for shaving, three years for fighting.

While San Francisco is the first to hire a social worker, other libraries may follow. As the economy languishes and cities shut down social programs, public libraries are becoming repositories for those who have been kicked out and turned away from all other places.

Camila Alire, president of the Chicago-based ALA, said that while libraries have long been refuges for the down and out, anecdotal reports underscore that they are dealing with more people than ever before with mental health issues and basic needs such as food and shelter.

"Public libraries are trying their best to serve their users and people who have traditionally been non-users," Alire said. "I hope that what the San Francisco Public Library has done by hiring a social worker serves as a model, because these people are educated and trained to help these patrons who have every right to use the public library system."

More libraries across the country are hiring therapists to train staff members how to handle stressful patrons. Edmond Otis, a psychotherapist, trains librarians how to talk to patrons who may be mentally ill or on drugs.

"There is a gigantic homeless population that basically 'passes' except nobody knows where they sleep," Otis said. "That population is growing. But we're looking at the mentally ill and drug addicted. And there are ways of talking to someone." That includes remaining calm, treating all patrons with respect, and setting rules and sticking to them, he said.

Some libraries are dealing with large numbers of destitute patrons.

In San Francisco, the main library, a six-story building with gleaming glass walls, is located in the Civic Center, where many homeless people congregate. It is near a neighborhood of single room occupancy hotels, soup kitchens and other service providers for the very poor. Some mornings, just after it opens, the library seems to have more people who appear to be homeless _ wearing half their clothes and carrying the rest _ than not.

Frank Bunnel, who is 53, comes every day carrying a large duffle bag and a blanket. "Sometimes I fall asleep here," he said.

For years, said Karen Strauss, the assistant chief librarian of the main branch, staff members could do little more than empathize with the desperate regulars who spend their days sitting among the stacks, reading, or just sitting, some with body odor that lingers in the air when they leave.

When other patrons have complained about the disturbances caused by mentally ill or drug addicted patrons, all the library could do was call its officer, a full-time city police sergeant.

Last year, the library decided to partner with the Department of Public Health to hire Leah Esguerra.

As resident social worker. Esguerra's delicate task is making herself visible and available to those who might want help without intruding on the privacy of those who do not.

She estimates that she has helped 200 people in the last six months, not all of them homeless or lacking basic needs. "Some people are depressed because they can't find a job," she said. "Or they've lost a loved one. When people ask for me, I go to them. Or through word of mouth those who haven't asked know about me."

John Banks, who is 40 and cannot remember how long he has lived unsheltered, or how it happened, said he might ask for Esguerra one day. For now, if he could blend into the walls, he would. That cannot be, not with his wheelchair stacked high with all he owns, like a pickup truck. To accommodate it, he must stick to open space, usually on the third floor near the computer station, where so many people can see him.

He doesn't read well, he said, so he skips the books and magazines, knowing the staff will let him be.

Yes, he said the other day, he might call for the social worker soon.

"I've got all this laundry to do," he said, gesturing to large plastic bags filled with clothes behind his back. "Maybe she can help with that."