Friday's request by the world's largest search engine company followed a federal judge's March 2011 rejection of a sweeping $125 million settlement of the now seven-year-old case. Talks to revive an accord later broke down.

Google has said it has scanned more than 20 million books, and posted English-language snippets of more than 4 million, since agreeing in 2004 with large research libraries to digitize current and out-of-print works for its Google Books website.

While Google planned to provide only snippets online to comply with copyright laws governing fair use, The Authors Guild and groups representing photographers and graphic artists complained that it amounted to "massive copyright infringement."

In a filing with the U.S. district court in Manhattan, Google said authors have shown no economic harm from its scanning and display of their works and the creation of a searchable index to find them.

The company also said authors actually benefit because the database helps people find and buy their books, and that there is a "significant public benefit" from providing access to information that might otherwise not be found.

"Google Books creates enormous transformative benefits without reducing the value of the authors' work," it said. "(It) therefore passes with ease the ultimate test of fair use."

Michael Boni, a lawyer for The Authors Guild, whose president is novelist-lawyer Scott Turow, said he asked the court on Friday to grant summary judgment in his client's favor.

He said his filing is not public because it refers to confidential Google documents. "We're grinding away," Boni said in an interview.

In rejecting the $125 million accord, Judge Denny Chin had said it went too far because it gave Google a "de facto monopoly" to copy books en masse without permission and served to "further entrench" its market power in online searches.

Among the libraries whose works have been scanned are those of Harvard University, Oxford University, Stanford University, the University of California, the University of Michigan, and the New York Public Library, Google has said.

The United States, Amazon.com Inc and Microsoft Corp had been among those to raise antitrust concerns about the settlement.

Chin began overseeing the Google case as a trial judge and kept jurisdiction after he was elevated in 2010 to the federal appeals court in New York.

He granted class-action status to authors in May, and said groups representing photographers and graphic artists may also sue. Individual plaintiffs in the case include former New York Yankees baseball pitcher Jim Bouton, the author of "Ball Four."

Google shares closed on Friday up $21.60, or 3.5 percent, at $634.96 on the Nasdaq, as U.S. stocks advanced broadly.

The case is The Authors Guild et al v. Google Inc, U.S. District Court, Southern District of New York, No. 05-08136.

(Reporting By Jonathan Stempel in New York; Editing by Steve Orlofsky, Toni Reinhold)

• A Permanent Economic Emergency