The History of the Copyright Laws

1923 is when the first copyright laws came into existence. In pre-1923 in America, there's no copyright on it. That means you can take that and you can republish it or make a derivative work out of it. 93% of works between 1923 and 1963 are actually in the public domain. After 1963 it changes, the copyright laws got really strict. So anything post 1963 I believe is like pretty much out of luck.