In this thoughtful treatise spurred by the 2015 death of African-American academic Sandra Bland in jail after a traffic stop, New Yorker writer Gladwell (The Tipping Point) aims to figure out the strategies people use to assess strangers-to "analyze, critique them, figure out where they came from, figure out how to fix them," in other words: to understand how to balance trust and safety. He uses a variety of examples from history and recent headlines...

"Chrissie is eight years old and she has a secret: she has just killed a boy. The feeling of it made her belly fizz like soda pop. Across her neighborhood, Chrissie's playmates and their parents are tearful and terrified. But Chrissie rules the roost - she's the best at wall-walking, she knows how to get free candy, and now she has a secret, thrilling power she doesn't get to experience much at home, where food is scarce and attention scarcer. Twenty...