During the term that followed, his enthusiasm spread through us like a contagion. “Don’t be afraid to disagree with me,” he used to say. “It shows you are thinking for yourselves, and that’s what you are here for.” Warming to such confidence, we felt we had to justify it by giving more than our best. And we did. Mr. Stone gave us the greatest gift a teacher can bestow—an awakening of a passion for learning. Question: According to the author, what is the most valuable thing that a teacher could give his students?