Originally Posted by AnemicOak
For the US it was copyrighted 10 April 1925 and the copyright was renewed 23 March 1953. Making it under copyright until January 2021.
But as the author died on 21 December 1940 (Exactly 72 years before the end of the world
), it's been out of copyright in life+70 countries since 1st January 2011, and in life+50 countries (like Canada) since 1st January 1991.