A federal judge rejected a lawsuit on Thursday by authors aimed at stopping Google’s book scanning project, ruling that Google’s plan to scan and digitise 20 million books constitutes fair use under US copyright laws.

The long-running dispute centred on Google’s Library Project in which the search giant reached agreements with several large libraries to scan their collections to provide information about the books and online excerpts.

Author and publisher groups argued that the practice was a violation of copyright, but Google reached a settlement with the publishers last year.

In his ruling Judge Denny Chin rejected the authors’ claims, and said the Google project offered numerous benefits to the public and to researchers. It also fell under the fair use doctrine of copyright law because “Google’s use of the copyrighted works is highly transformative,” he ruled.

Not only does the Google project provide “a new and efficient way for readers and researchers to find books,” he added, but it “has become an essential research tool, as it helps librarians identify and find research sources, it makes the process of interlibrary lending more efficient, and it facilitates finding and checking citations.”