I know a simpler rule: Just have a look at my list of recommended nonfiction books: https://github.com/asmaier/littlelists/blob/master/books_nonfiction.md https

I know a simpler rule: Just have a look at my list of recommended nonfiction books: https://github.com/asmaier/littlelists/blob/master/books_nonfiction.md https://github.com/asmaier/littlelists/blob/master/books_non... ;-)