When you’re a spy, you meet a lot of experts. You meet area experts, scientific and technical experts, and experts on economics, politics, and diplomacy. But experts are everywhere. If you’re in business, you might want an expert in marketing to help you. Or an expert in quality control. Or an expert in product distribution. But how do you judge if they’re really an expert? Most of the time, you rely on two indicators: Credentials in the field you care about and Experience ge

For most of baseball history, major league scouts were looking for “Five-Tool Players.” To be a Five-Tool Player, you need to be better than most other players in five different categories: Batting average, hitting for power (extra bases), speed, throwing, and fielding. Which is hard. It’s hard to be better than most other major-league players in one of those categories, much less five. Five-Tool Players are some of the best players in baseball history: Hank Aaron, Alex Rodri