Google's co-founder Larry Page was a Michigan graduate

Speaking to the Association of American Publishers, which is suing Google, Mary Sue Coleman called Google Book Search "legal, ethical and noble".

It would preserve books from decay but would not infringe copyright, she said.

Ms Coleman heads the University of Michigan, which is participating in the project and numbers Google founder Larry Page among its graduates.

The AAP, which includes major publishers such as Penguin, filed a lawsuit against Google in New York in October 2005 claiming that Google will infringe their copyrights.

We were digitising books long before Google knocked on our door, and we will continue our preservation efforts long after our contract with Google ends Mary Sue Coleman President, University of Michigan Google's right to scan

In a mission statement posted on its website, Google likened its Book Search project to US President John F Kennedy's drive to put a man on the moon, an "unthinkable" idea realised within a decade.

The company insists it will not allow copyright infringement, describing Google Book Search as a "book-finding tool, not a book-reading-tool".

Material from Michigan, Stanford, Harvard, Oxford and the New York Public Library is being digitised.

Deep-held belief

Addressing an audience of scholars and professional publishers, Ms Coleman described her university's partnership with Google in terms of a "mission".

The university and the internet giant shared a belief in core values, she said: "The preservation of books; worldwide access to information; and, most importantly, the public good of the diffusion of knowledge."

Many books stored in traditional libraries are under threat of decay

The University of Michigan had already begun digitising many of the works in its collections before the suggestion four years ago by Larry Page that Google take over and speed up the process, Ms Coleman said.

"We were digitising books long before Google knocked on our door, and we will continue our preservation efforts long after our contract with Google ends," she added.

"As one of our librarians says: 'We believed in this forever.' Google Book Search complements our work. It amplifies our efforts, and reduces our costs.

"It does not replace books, but instead expands their presence in the marketplace."

Publishers angry

The AAP launched a lawsuit against Google when discussions over the company's project broke down in October.

Google hopes its plans will boost book sales

Five major publishers companies backed the claim: McGraw-Hill, Pearson Education, the Penguin Group (USA), Simon & Schuster and John Wiley & Sons.

The action, filed in New York, aims to secure a legal declaration that Google infringes copyright when it scans entire copyrighted books.

It also seeks a court order preventing Google from digitising copyrighted books without permission of the copyright owner.

There also remain fears that Google intends to place adverts on search result pages, in effect generating lucrative revenue even as it "infringes" copyright.