Malcolm Gladwell was born in 1963, in England. He moved to Canada as a child, and still identifies as a Canadian author. His new book, “David and Goliath,” “is a very Canadian sort of book,” he says. The theme of his book is that underdogs — Davids — win over powerful opponents — Goliaths — more often than people think. “David and Goliath,” Gladwell says, is “Canadian in its suspicion of bigness and wealth and power.” . . . Christopher Chabris is a psychology professor at Union College in New York. In 2013, he studied Gladwell’s newest book in order to write a review for the Wall Street Journal. Here’s what Chabris found : In Gladwell’s previous book people like attorney David Boies were said to be successful because of their environment (his parents were teachers) and because of hours of work (he debated in college). Now, Boies’ success happens for a simpler, more uplifting reason: Because he was dyslexic. Gladwell calls dyslexia a “desirable difficulty.” But there was a p...