6. a small strip of coloured cloth signifying membership of an order or award of military decoration, prize, or other distinction. 7. a small, usually looped, strip of coloured cloth worn to signify support for a charity or cause: a red AIDS ribbon.
The books burned were Jewish, Marxist, Bolshevik, or other disreputable or non-German books. These included the works of Heinrich Heine, Sigmund Freud, Thomas Mann, Erich Maria Remarque, Albert Einstein, Walter Benjamin, Karl Marx, Jack London and Margaret Sanger.
Word count is what you want to look at, but even then pages can be pretty irrelevant. Books are formatted differently, printed on different sizes of paper, with different fonts and different spacings. A 300 page book could range in word count from 40,000 to 140,000 depending on these considerations.