I think issybird has a right to her opinions.
Her reasoning makes sense. Who am I to say what is or isn't literature to someone else. It is somewhat subjective. And, I think the non-fiction category makes it even more fuzzy. I couldn't find a definitive list of criteria when I searched the internet because everybody has their opinions.
I did like this definition that I found on about.com, even though I don't think it's meaty or specific enough:
http://classiclit.about.com/od/liter...hatisliter.htm
It says that "literature introduces us to new worlds of experience." I did get that out of this book since I have not read any books that absorb you in the experiences of a Japanese prisoner of war. I also learned more about Japanese culture.
Somewhat off topic, I'm looking forward to reading the Carlo Levi book in the future. The town of Aliano has a great photograph collection, which helps to picture where he was exiled.
http://www.aliano.it/aliano/galleria-fotografica.php