A federal appeals court on Tuesday upheld the right of universities, in conjunction with Google, to scan millions of library books without the authors' permission.

The 2nd US Circuit Court of Appeals, ruling in a case brought by the Authors Guild and other writers' groups, argued that the universities were not breaching federal copyright law, because the institutions were protected by the so-called "fair use" doctrine. More than 73 percent of the volumes were copyrighted.

The guild accused 13 universities in all of copyright infringement for reproducing more than 10 million works without permission and including them in what is called the HathiTrust Digital Library (HDL) available at 80 universities. The institutions named in the case include the University of California, Cornell University, Indiana University, and the University of Michigan.

Those with "certified print disabilities" like the blind may access the complete scanned works, which the New York-based appeals court also found are preserved indefinitely because of their digital reproduction. Those without disabilities may only search keywords in the books unless an author grants greater permission.

"We have no reason to think that these copies are excessive or unreasonable in relation to the purposes identified by the Libraries and permitted by the law of copyright. In sum, even viewing the evidence in the light most favorable to the Authors, the record demonstrates that these copies are reasonably necessary to facilitate the services HDL provides to the public and to mitigate the risk of disaster or data loss," the court wrote (PDF).

The fair use doctrine is a defense to copyright infringement and generally may be asserted for reasons such as scholarship and research, teaching, news reporting, commentary, parody, and criticism.

According to the appeals court:

It is not disputed that, in order to perform a full‐text search of books, the Libraries must first create digital copies of the entire books. Importantly, as we have seen, the HDL does not allow users to view any portion of the books they are searching. Consequently, in providing this service, the HDL does not add into circulation any new, human‐readable copies of any books. Instead, the HDL simply permits users to 'word search'—that is, to locate where specific words or phrases appear in the digitized books. Applying the relevant factors, we conclude that this use is a fair use.

The court added that making volumes available in their entirety to the disabled "is an example of fair use."

Daniel Goldstein, who argued the case on behalf of the disabled, said the decision "changed for the better the lives of print-disabled Americans, that is, those who cannot readily access printed text, whether because of blindness, arthritis, dyslexia, cerebral palsy, upper spinal cord injury, or a host of other conditions."

The guild did not immediately comment on the decision, which largely affirms a 2012 lower court ruling.