Well...first off, first off, according to the United States Copyright Laws, EVERY book published 95 years or more from the current date is in the Public Domain! That means that each new year, MORE books find their way into the Public Domain automatically! AWESOME!
The second curiosity we wish to explore is a specific qualifier applied by Copyright Law to constitute copyright protection...if the Copyright Office determines that a human being did not create the work, they will refuse to register the copyright claim! Here is why THAT FACT is such a huge deal => Written content produced by AI (artificial intelligence) does NOT qualify for copyright protection because it wasn't written by a HUMAN! Yeah!
So what happens when we marry together written content from books & magazines in the Public Domain with AI-Based writing software? MAGIC!