"Either one," Q says evenly. "You said it was destroyed, disposed of." he goes on. "So in effect, it was wasted."
"All right, but why?" Q looks from the book to Severus, puzzled. "I did check it for curses and hexes Severus," he says. "I might not have been the best Defense teacher Hogwarts ever had, but I do know my business." He picks up the book gingerly. "It seems a shame to deface it."