The Supreme Court announced Monday that it is declining to hear a copyright challenge against Google Books by the Authors Guild, upholding a recent Appeals Court decision that the tech giant’s book-scanning project is protected under fair use. Google has spent much of the last decade fighting the Authors Guild and other writers for the right to scan books and display excerpts online without explicit permission from the publisher. By refusing to hear the case, the Supreme Court has decided that Google Books is, in fact, protected under copyright law.

At the heart of this case is the concept of fair use, which is a core part of U.S. copyright law. Essentially, fair use grants some protections against charges of copyright infringement if certain conditions are met. According to the U.S. Copyright Office, in order to determine whether a work falls under fair use a judge must consider what the original work is, how it is being used, how much of the work is being used and whether the new work takes an audience away from its source. Each case, however, has to be judged on an individual basis, David Kravets reports for Ars Technica.

Since Google began scanning books in 2004, it has digitized more than 20 million books in its collection. The Authors Guild sued the tech company in 2005, arguing that the database infringed on many books copyrights because Google did not ask for permission and was publishing the copies for people to read for free online. Google in turn argued that it was transforming the original books by making them searchable and easier for readers to preview, the BBC reports.

"We are grateful that the court has agreed to uphold the decision of the Second Circuit, which concluded that Google Books is transformative and consistent with copyright law," a Google spokesperson said in a statement. "The product acts like a card catalog for the digital age by giving people a new way to find and buy books while at the same time advancing the interests of authors."

After a decade of legal battles, a lower court ruled in favor of Google last fall. Because the Supreme Court decided not to take on this case, that ruling will stand. None of the justices commented on the case other than to note that Justice Elena Kagan did not participate, Kravets writes.

While Google doesn’t directly make money off of the book previews it publishes online or from sales if readers decide to buy the book, it could have faced having to pay billions of dollars in damages to authors if it lost the case. Also, because the Authors Guild took issue with the indexed, searchable snippets that Google published for its scanned books, BoingBoing’s Cory Doctorow argued that the lawsuit could have threatened the very idea of internet search engines.

While this case may be closed, it won't be the last time that advocates for fair use and artists seeking compensation butt heads.