Google can appeal the granting of class status to authors suing the search engine company over its plan to create the world's largest digital books library.
The 2nd US Circuit Court of Appeals in New York granted Google permission to challenge a 31 May decision by Circuit Judge Denny Chin letting authors sue as a group.
If Google wins it could save the search engine billions of dollars and force the Authors Guild, a group representing authors, to fight each case one at a time.
Google has already scanned more than 20 million books, and the Guild has said Google should pay $750 for each book copied.
Chin said it would be unfair to force Authors Guild members to sue individually. It would mean that there would be different results and much higher legal costs. What alarmed Google however was that he also added the phrase "given the sweeping and undiscriminating nature of Google's unauthorised copying" which probably means it is toast if it ever comes to a ruling.
Google told the Appeals court that case-by-case determinations were needed to show whether it was making "fair use" of the plaintiffs' works.
It said that "fair use" would be its main defence and Google should not be forced to litigate without the full benefit of its principal defence.
According to Reuters Google began creating the library after the company agreed in 2004 with several major research libraries to digitise current and out-of-print works.
Harvard University, Oxford University, Stanford University, the University of California, the University of Michigan and the New York Public Library have all had their collections scanned.
In March last year Chin rejected a $125 million settlement of the case, saying it gave Google a "de facto monopoly" to copy books en masse without permission.