I did not think Delia Goetz was dead apparently she died in 1996. So it appears her book is still has copyright.
The book is available online with the following excerpt "[1954, copyright not registered or renewed]", but in the states one does not have to register to have their work copyright
Here is the site.
http://www.sacred-texts.com/nam/maya/pvgm/
You know what is weird is I know mobiread has the book "Think and Grow Rich" by Napoleon Hill. I assumed all his works where PD. If he died in 1970 then his book is still CR. (Unless he PD the book)