Google opened the doors of its online library yesterday, allowing users to search its collection of digitised public domain works. But Google Print is only offering access to public domain works for now, amid controversy over plans to include copyrighted works.

"Today we welcome the world to our library," said Mary Sue Coleman, President of the University of Michigan, which is participating in the scheme. "Anyone with an internet connection can search the text of and read the compelling narratives, historical accounts and classic works offered today, and in doing so access a world of ideas, knowledge and discovery."

Announced late last year, the Google Print Library Project involves the scanning and digitisation of millions of published books from the collections of three major academic libraries – Stanford University, Harvard University and the University of Michigan – from which Google plans to create an online, searchable database.

Oxford University and the New York Public Library are also participating in the Library Project, but are only making available works in the public domain.

A user searching Google Print is presented with links on the results pages when there are books relevant to his query. Clicking on a title will deliver a page from which the user can either browse the full text of the work – if copyright has expired – or brief excerpts and/or bibliographic data where the work is still protected by copyright. Links to sellers are also provided.

Users can search the Google Print index directly, but it is also integrated into the usual Google search results pages.

According to Google, the programme will increase the viability of in and out of print books and generate book sales. Users will be able to search across library collections, including out of print books and titles that weren't previously available anywhere but on a library shelf.

But the scheme has not been universally welcomed. Authors and publishers have criticised the plan, expressing concern about how Google would protect the rights of authors and publishers whose books it had scanned.

Under pressure, Google announced in May that it was temporarily halting the scanning of in-copyright works, so that copyright holders could let the firm know if their works should not be scanned.

It was due to begin scanning copyrighted works again in 1st November, but has still to restart the process, according to CNET News.

In the meantime, Google has been hit with two lawsuits over the project. The Association of American Publishers and the Authors Guild separately accuse the search giant of infringing copyright by digitally copying and distributing their members' works without the permission of copyright owners.

Google denies any copyright infringement. For books not in the public domain, the company says it only shows small snippets of the work [http://print.google.com/googleprint/screenshots.html#excerpt], unless the publisher or copyright holder has given Google permission to show more.

Copying a small snippet of a work may be acceptable in copyright law; but Google appears to be copying much more than that. An entire book is being scanned without permission – albeit Google only displays a small snippet of the text.

We are processing your request. \n Thank you for your patience. An error occurred. This could be due to inactivity on the page - please try again.