It's No Secret - Millions of Books Are Openly in the Public... | HathiTrust Digital Library

"Since 2008 the HathiTrust Copyright Review Program has been researching hundreds of thousands of books to find ones that are in the public domain and can be opened for view in the HathiTrust Digital Library. Over the past 11 years, 168 people across North America have worked together for a common goal: the ability to share public domain works from our libraries. As of September 2019, the HathiTrust Copyright Review Program has performed copyright reviews on 506,989 US publications; of those, 302,915 (59.7%) have been determined to be in the public domain in the United States. The opening of these works in HathiTrust has brought the total of openly available volumes to 6,540,522.

The Copyright Review Program, now an operational program of HathiTrust, began as a grant-funded ambition of the University of Michigan Library, under the leadership of Melissa Levine. The Institute of Museum and Library Services (IMLS) funded three consecutive grants enabling the University of Michigan Library and grant collaborators to build a copyright review management system. The program is still going strong eleven years later, resulting in hundreds of publications determined to be in the public domain each week.

One way the Copyright Review Program determines the copyright status of items in the HathiTrust corpus is to determine whether they were properly renewed. In the United States, the copyright in works published between 1924 and 1964 had to be renewed about 28 years after the item was published; works could move into the public domain when their initial term of protection expired. The Stanford Copyright Renewal Database was one of the first to host monograph renewal records in an open access database, but much of the initial copyright registration information remains difficult to search. ..."