HathiTrust, an online academic library that includes more than 10 million works, won a legal victory this month, strengthening the cause of fair use. At issue is what uses can legally be made of HathiTrust’s online repository, which was created by five university libraries, drawing on a partnership with Google to scan millions of books and other materials. The Authors Guild, along with other professional groups and individual authors, filed a lawsuit last September seeking to shut down “the systematic, concerted, widespread, and unauthorized reproduction” of copyrighted material. But this month, Judge Harold Baer Jr. of the U.S. District Court in Manhattan declared that the project’s scanning and use of copyrighted works counted as fair use under copyright law.