Google Inc. has suspended some of its project to place a vast selection of books online, bowing at least temporarily to concerns of publishers who fear scanning material into the world's most powerful search engine will lead to unauthorized use and duplication of copyrighted material.

Google launched its test service, Google Print, in October and later started its Google Print Library Project, an attempt to scan books in five libraries to make them searchable online. Mountain View, Calif.-based Google postponed further scanning of copyrighted books from libraries at Harvard University, the University of Michigan and Stanford University until November. Until then, copyright holders can opt out of the scanning by contacting Google directly, the company said.

The New York Public Library and Oxford University, which also partnered with Google, have agreed only to share a limited number of materials, including books no longer protected by copyright.

"We think most publishers and authors will choose to participate in the publisher program in order to introduce their work to countless readers around the world," Google Print product manager Adam M. Smith said in a posting on the company's official Web log. "But we know that not everyone agrees, and we want to do our best to respect their views too. So now, any and all copyright holders . . . can tell us which books they'd prefer that we not scan if we find them in a library," Smith wrote in his posting.

Some books are already viewable at other online sites. Web-based retailer, for example, allows prospective buyers to read the first several pages of some books. To put that content online, Amazon negotiates deals with the publisher or author. Google's search service would only allow users to look up several sentences in copyrighted materials, not the entire book.

"What we're doing here is completely in line with the principles of fair use," Smith said in an interview. "We think this will help more users discover their books, and buy their books."

But publishers say Google has pushed the online boundary much further, rewriting copyright law by scanning in books in their entirety and putting the burden of copyright protection on authors and publishing houses to contact Google if they do not want their items searchable online.

"We think they have to stop this entirely," said Patricia S. Schroeder, president and chief executive of the American Association of Publishers, which represents more than 300 publishers. International publishers are equally concerned about having to opt out of having their materials put online, she said. "This idea that the rights holder has all the burden . . . that's crazy," she said, adding that her group has been trying since June to privately negotiate an alternative solution with Google.

Google, which through mapping, video and image products aims to make most of the world searchable online, said it is trying to balance its lofty goals with fairness to the copyright holders.

"The goal of Google Print is ambitious: to make the full text of all the world's books searchable by anyone," Smith said in his posting. "These books are hard to find now, and for most of them, no full-text search exists. We think that making books easier to find will have a positive impact on the world."

That intention is worth pursuing, said David Sohn, staff counsel at the Center for Democracy and Technology, a digital policy think tank.

"It's an example of how the Internet offers a lot of great new opportunities for disseminating information, and it is important to resolve those [copyright] issues so we really take advantage of those opportunities," Sohn said.