Google has announced a long-term project to put 15 million books from seven of the world's top libraries online.

The libraries of Harvard, Stanford, the University of Michigan, the New York Public Library and the University of Oxford, including the Bodleian, will be put online in a project expected to take six years at a cost of more than $100m.

"Even before we started Google, we dreamed of making the incredible breadth of information that librarians so lovingly organise searchable online," said Google co-founder Larry Page.

"Today we are pleased to announce this programme to digitise the collections of these amazing libraries so that every Google user can search them instantly."

Books and periodicals will be scanned and made available for search using Google. Copyright material will not be displayed, however.

"We believe passionately that such universal access to the world's printed treasures is mission-critical for today's great public universities," said Mary Sue Coleman, president of the University of Michigan.