“This agreement expands access to many of these hard-to-find books in a way that is great for Google, great for authors, great for publishers and great for readers,” said Alexander Macgillivray, the Google lawyer who led the settlement negotiations with the Association of American Publishers and the Authors Guild.

Most of the critics, which include copyright specialists, antitrust scholars and some librarians, agree that the public will benefit. But they say others should also have rights to orphan works. And they oppose what they say amounts to the rewriting, through a private deal rather than through legislation, of the copyright rules for millions of texts.

“They are doing an end run around the legislative process,” said Brewster Kahle, founder of the Open Content Alliance, which is working to build a digital library with few restrictions.

Opposition to the 134-page agreement, which the parties announced in October, has been building slowly as its implications have become clearer. Groups that plan to raise concerns with the court include the American Library Association, the Institute for Information Law and Policy at New York Law School and a group of lawyers led by Prof. Charles R. Nesson of Harvard Law School. It is not clear that any group will oppose the settlement outright.

The groups representing publishers and authors, which filed a class-action lawsuit against Google in 2005 in the Federal District Court for the Southern District of New York on behalf of their members, are defending the settlement, as are some librarians at major universities.

“What we were establishing was a renewed access to a huge corpus of material that was essentially lost in the bowels of a few great libraries,” said Richard Sarnoff, former chairman of the Association of American Publishers and co-chairman of the American unit of Bertelsmann, the parent company of Random House.

The lawsuit claimed that Google’s practice of showing snippets of copyrighted books in search results was copyright infringement. Google insisted that it was protected by fair use provisions of copyright law.