That's irksome. I hope you at least enjoy the book?

I keep getting free unsolicited calculus textbooks in the mail, all of which have some sort of language like "review copy do not sell" on the cover. I need to figure out an ethical thing do with them, because I don't really need more calculus books and there are people who _do_, but if I give them away I want to make sure they don't just wind up in the used textbook market because a student wants to make a paltry $20.