I wrote earlier (at https://tinyurl.com/y25bkuyk) that many books published between 1923 to 1964 are now in the public domain. An article by Karl Bode in the Vice.com web site provides an update to a project to make the books available to the public at no charge:
“A coalition of archivists, activists, and libraries are working overtime to make it easier to identify the many books that are secretly in the public domain, digitize them, and make them freely available online to everyone. The people behind the effort are now hoping to upload these books to the Internet Archive, one of the largest digital archives on the internet.”
I hope this includes a number of genealogy books. You can read the updated article at: https://tinyurl.com/yy2xh7gq.