On Friday, I received three handwritten letters from middle-school kids who had read The Hundred. They came from children in a school in the Bronx, who had been introduced to the book through their teacher.

I was so astounded and moved by these letters, and I wanted to share a couple of specific quotes. I trembled as I read the letters, for I knew that something I had done really mattered to a child. While a praiseworthy review on Amazon or Goodreads always makes my heart soar, these were diff...