into the flight he glanced across and noticed that the man was reading Hawking’s book. Without having been introduced and before the usual small talk, they struck up a conversation about it.

“What do you think of it?” Linde asked.

“Fascinating,” said the businessman. “I can’t put it down.”

“Oh, that’s interesting,” the scientist replied. “I found it quite heavy going in places and didn’t fully understand some parts.”

At which point the businessman closed the book on his lap, leaned across with a compassionate smile, and said, “Let me explain. . . .”