Word for word, bit by bit: no matter the promise, opinions are split on Google's plans to scan library books.

Don't look now, but things have been disappearing from library buildings at a rapid pace. But don't call security: It's all perfectly legal.

Remember card catalogs, rubber stamps and pneumatic tubes? They've all vanished in favor of computers, printers and e-mail. What will disappear next? The books themselves? That's not as far-fetched as it sounds.

In December 2004, Google Inc., owner of the world's most popular Web search engine (www.google.com), announced that it would start scanning thousands of books from some of the world's largest library systems. Web surfers will soon be able to browse the books at the Google Web site without having to worry about getting them dirty or returning them to a library on time.

The scanning project is part of the Google Print program, a service that helps publishers get their content online. In addition to text, the graphics, photos and illustrations from the books will also be scanned and indexed. The goal, according to Google, is to provide more access to more books to more people. There's also a commercial side. As readers access the scanned books, they will be offered the chance to buy them at an online bookstore.

Libraries included in the Google project are Harvard University, Stanford University, the University of Michigan, the New York Public Library and the University of Oxford in the United Kingdom.

"We are exhilarated to join a partnership with Google that perfectly advances our mission as a great public university to share knowledge within the academic community and far beyond it," said University of Michigan President Mary Sue Coleman in a press release. The university noted that Google will digitize the university's entire seven-million-volume collection in the space of a few years.

Some librarians have expressed misgivings. Some have said that the scanning project would create the cyberspace equivalent of Cliffs Notes, allowing readers to browse and search through books without actually reading them through.

Michael Gorman, dean of library services at the Henry Madden Library at California State University in Fresno, expressed misgivings in a commentary published in The Los Angeles Times a few days after Google's announcement.

"The books in great libraries are much more than the sum of their parts," wrote Gorman, who is president-elect of the American Library Association (ALA). "They are designed to be read sequentially and cumulatively, so that the reader gains knowledge in the reading." The ALA itself, which has more than 64,000 institutional and individual members, has not taken a position on Google's project.

Rayah Levy, a student at the Graduate School of Library and Information Science at Simmons College in Boston, hopes libraries don't use it as an excuse for disposing of the original books.

Levy says libraries need a long-term, data-storage plan to make sure that the computers of tomorrow will be able to read the data from the books scanned today.

"It doesn't bother me that they're doing this," says Levy, a member of the Massachusetts Black Librarians Association. "The thing is the whole preservation issue."

Levy says she is also worried that scanning books leaves room for tampering or editing. She added that readers need to have assurance that scanned data is authentic and accurate.

Many libraries already scan fragile, valuable or rare books to make the contents available to more people while reducing wear and tear on their collections.

Although Google will be using expensive automated equipment that can scan books quickly, many affordable book scanners are designed for individuals and small libraries. For example, Plustek Inc.'s OpticBook 300 (408-392-0859, www.plustek.com, $249) desktop scanner is designed specifically for books.

The scanning glass extends almost all the way to the edge, allowing you to lay book pages flat against the glass while the spine of the book rests on the unit's corner. According to Plustek, the unit's shadow-elimination element provides additional light near the book spine, thus reducing shadows and providing even exposure to book pages.

Of course, book scanning raises copyright and intellectual-property issues. Google said that only books in the public domain will be fully scanned. Copyrighted books will only have excerpts made available.

Will large-scale book scanning knock real books off of library shelves? Maybe a few. If the contents of popular public-domain books are available online, libraries would need fewer copies.

Robert S. Anthony is a personal computing and technology writer in Brooklyn, New York.