why not say sell it and give the money to something you like, like charity. Per the author's website ( https://cs.brown.edu/~sk/ https://cs.brown.edu/~sk/ ), h

why not say sell it and give the money to something you like, like charity. Per the author's website ( https://cs.brown.edu/~sk/ https://cs.brown.edu/~sk/ ), he is a dedicated educator. Maybe he explicitly or implicitly intended the publication of this work under a Creative Commons license to be an exercise of charity (in the "love your neighbor" sense), kindness, goodness, and/or generosity.