A WOMAN in Pittsburgh marched into the library with an interest in the Civil War. She left with 23 books on the subject -- nearly every one in the building.
After months of keeping those books, she struck again at another branch library. ''It was at that point that the bells and whistles worked,'' says Loretta O'Brien, deputy director of Carnegie Public Library.
This library-book larsonist was nabbed (the books remain at large) by an elaborate computer network that traces the comings and goings of each book in circulation, much as the FBI stalks criminals.
But librarians say computerization alone won't stop the financial drain from thieves and literary scofflaws. Yesterday's quiet keepers of Kafka are starting to play corporate hardball, using credit bureaus, collection agencies, and even the courts to retrieve overdue books and fines.
''Computers make books easier to track, but the issue is still recovery, and I don't think we've figured out any great way of doing that,'' Ms. O'Brien says.
Libraries lose in the range of $375 million a year in unreturned books, compact discs, videos, and films. Though that represents only 1 percent of the 1.5 billion books shuttling in and out of library doors a year, that's no small change for institutions pummeled by ever-slimmer budgets while the price of books soars.
The dwindling resources are forcing libraries nationwide to look for new solutions for this nagging problem. In Pittsburgh, a credit bureau handles the most egregious unreturned book cases. In Virginia, state tax auditors subtract library owings from tax refunds and lottery winnings. And in Boston, serious offenders are granted a day in court.
To combat the loss of between 5 and 10 percent of the books that don't make it back on the shelves in Forsyth County, N.C., libraries send borrowers' names to someone who commands attention -- the attorney general.
Librarians stress that most scofflaw borrowers are simply negligent, not malicious. ''It fell into the dresser, got kicked behind the waste basket, or the dog ate it, in most cases,'' says George Needham, director of the Chicago-based Public Library Association. People moving out of town are often the worst offenders, he says.
And then there's the Boston library, heavily used by the many college students in the area. ''You get people who think they should be able to keep a book for the whole semester,'' says Cynthia Phillips, Boston Public Library's circulation supervisor.
NOT only strong-arming patrons, libraries are encouraging users to return books on time with a more gentle touch as well. ''For us it's very important not to create barriers,'' Pittsburgh's O'Brien says. ''We are far more interested in getting the books back than [punishing patrons].''
If borrowers return their overdue books with nonperishable food items, all fees are forgiven at some libraries. Amnesty weeks clear the record for other recalcitrant readers who return books.
But these measures generally are not as effective as get-tough policies. ''You never get as much back as you think you will,'' Ms. Phillips says of the Boston library's nearly concluded amnesty.
In addition to trying to marshal their collections, libraries face a myriad of other demands. Keeping current with the training and equipment needed to launch on-line computer programs is ''a bit like loading mercury with a pitchfork,'' Mr. Needham says. Federally funded outreach programs are threatened by current budget-balancing plans. And libraries have more users than ever. Some 21 percent of adults use libraries, according to a 1991 study, compared with the 8 percent who frequented them in 1948.
But reining in the books remains a top priority. ''Libraries are conservators of their collections,'' Needham says. ''They have a responsibility to make sure that the materials don't walk.''