Adolf Hitler’s book Mein Kampf entered the public domain at the beginning of 2016, because Hitler’s been dead for 70 years. That's a long time. Who was profiting from the book’s publication all those years? And who will profit now that anyone can use it? And why would anyone want to?
According to Simon from Today I Found Out, Hitler himself made a boatload of money from the volume. After his death, the financial arrangements regarding Mein Kempf got more complicated. Read more about it at Today I Found Out. -Thanks, Daven!