I've had good luck getting Google to mark books as public domain, at least if they are government publications. Here's what I do: I click on the "Report an issu

I've had good luck getting Google to mark books as public domain, at least if they are government publications. Here's what I do: I click on the "Report an issue" link at the bottom, select "I have a question or feedback about a book", and fill out the form, selecting "I’d like to see the entire book, and I believe the book is in the public domain" as the reason. Doesn't work every time, but I'd guess it has worked over 90% of the time for me. Might work for other reasons too. I don't know at the moment, but I'll give it a shot at the next opportunity I have.