The Jacob Burns Law Library [at George Washington University] has published a new online collection: "Pre-1870 Copyright Records." "The collection provides access to over 2,000 pages of digitized U.S. copyright records created prior to 1870 that had generally been assumed lost. The records were tracked down and digitized by Zvi S. Rosen, currently a Professorial Lecturer in Law and Visiting Scholar at The George Washington University Law School."
H-HistBibl is an international network of librarians, archivists, curators, and scholars interested in the practice and study of bibliographic and library services to support the study and teaching of history.
An analysis of the evolution of the Google Book project and its current state:
Scott Rosenberg, "How Google Book Search Got Lost," Backchannel, April 11, 2017, https://backchannel.com/how-google-book-search-got-lost-c2d2cf77121d