You should go and tell that person not to throw their books like that. There are many people who cannot study....they do not have books with them. Or they can even give it in charity to poor people. Books are of great use. They give us great knowledge. Without books no one can study or got education. There are may people who can read or want to read but do not have book. You help those people by giving these books to them if you do not need it. It is at least better than throwing these books.