Microsoft is releasing its Live Search Books, a rival to Google's Book Search, in test, or beta, version in the US.

The digital archive will include books from the collections of the British Library, the University of California and the University of Toronto.

Books from three other institutions will be added in January 2007.

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All the books currently included in the project will be non-copyrighted but later it will also add copyrighted work that publishers have given permission to include in the project.

"We feel very strongly about copyright. We don't do any mass scanning of in-copyright works," said Danielle Tiedt, the general manager of Live Search Selection for Microsoft.

Initially the database of available books will be searchable from the book search engine's home page or as a category on the main Windows Live Search page.

Later Microsoft plans to integrate all the books scanned into its general search engine.

"What we are focusing more of our efforts on for live searching is integrating all of those content types together to give you the most relevant results. If, for example, it's a search on historical content, chances are the most authoritative content may be found in a books search," said Ms Tiedt.

The system has a feature called "search inside a book" which will allow users to search the full text of books.

"We've focused on making the search experience really impactful...People will have full access to all of the text," said Ms Tiedt.

A separate global digital library plan by Google is also under way.

The search giant is spending $200m (�110m) to create a digital archive of millions of books from four top US libraries. It is also digitising out-of-copyright books from the UK's Oxford University.

In contrast to Microsoft Google's plans include adding both copyright and non-copyright books from participating institutions.