Marcus came to the end of a page, and he lifted his right hand to turn it, and his hand would not obey him.

There was a faint, involuntary tremble in it, a small betrayal that ran through his fingers as he reached for the thin paper, and the page slipped away from him.

He paused.

I watched him pause, watched him swallow hard, watched something cross his face for just an instant before he mastered it.

And then, smoothly, without breaking the flow of the story or letting his warm smile slip even slightly, he brought his left hand across and used it to gently turn the page instead, and he kept his eyes on the boy’s face the whole time, kept the funny voice going, so that the child would never once notice that anything was wrong.

It was such a small thing.