Yet the Internet - with its dark corners of child pornography and hate crime - has also thrust some librarians into the uncomfortable role of cybercop.

Federal laws and local pressures have created a patchwork of policies that often differ from library to library, with some installing Internet filters and others telling patrons they must police themselves - and their children.

Last week, authorities arrested a Nutley man who they said was downloading child pornography on the Montvale public library's computer. The arrest led Bergen County Prosecutor John Molinelli to suggest that local libraries consider installing tracking systems.

Tom Bonnell, a trustee of the Montvale library, said the responsibility for Internet exposure there is where it should be: on a child's parent or guardian.

"We are not guardians for community values. We don't decide societal norms," Bonnell said. "We provide access to information resources. That's what libraries do."

Under federal law, libraries that receive federal funds must install a content filter to block obscene visual materials. Montvale, like many suburban libraries, can opt out of filtering because it doesn't accept federal money.

The law is a sore point for librarians, who feel filters are imperfect tools that often block access to useful and innocent information. People seeking information on breast cancer or rape prevention, for example, might be blocked.

"Filters are dumb," said Juliette Sobon, director of the Washington Township library. "The three letters s-e-x, right? It's in a lot of words, like Middlesex, the title of a book."

If patrons in Washington Township view forbidden sites, the librarians will know: The monitors are positioned in full view of the circulation desk, Sobon said, adding that there haven't been any significant problems.

Atlantic County libraries, which accept federal funds, have filtering software on all computers. But adults can enable an Internet browser that doesn't use the filter, an option not available on the children's computers.

The monitors also have polarizing screens that block people's views from either side, said director William D. Paullin. That creates more privacy for online banking or for researching delicate topics like health or divorce advice, he said.

Even if the law didn't require it, the Atlantic libraries would still filter, Paullin said. A series of public forums revealed that library patrons had real concerns about pornography and other content.

Next year, 20 Bergen County libraries will try registration software, mostly to help them manage high demand for Internet use by having patrons sign up for specific time slots, said Robert White, the executive director of the Bergen County Cooperative Library System.

"You don't ID someone to look in a book," said Patricia Tumulty, executive director of the New Jersey Library Association. "That's not the library philosophy."

Teaneck Councilman Paul Ostrow, who serves on his township's library board, thinks it may be time for local libraries to consider filtering software.

"While we have a responsibility to stimulate knowledge in children, we also have a responsibility to make sure they're safe," he said. "Just like a community provides crossing guards on streets to protect children, possibly the library should provide guards on computers."

Wayne's library director, Jody Treadway, thinks her system has struck a good balance between permitting information access and preventing crime and indecent exposure.

The Wayne library's 53 computers use a filtering software with six levels. Patrons choose the filtering intensity when they sign up for a library card for themselves or their kids. The choices range from no filtering to very high settings that screen for pornography, online gambling, drug information, racist sites - and even dating/personals sites.

"Smut will always be with us, along with incredibly useful stuff," Bonnell said. "The antidote to smut and indecent information is not less information - it's more information."

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