I called Emmett Till's mom out of the blue. She picked up the phone and changed my life.

"I expected her to say, 'How did you get my number?' I expected her to hang up. But she didn't." I can’t remember what was written in the tiny notebook, but I do remember the handwriting: large, child-like, mostly cursive, looping letters in slightly faded pencil. I stood in a dim Chicago basement …