In The Smartest Kids in the World, Amanda Ripley investigates what makes some countries’ education systems so successful. In Finland, teachers are trained like elite professionals—only 20% of applicants get accepted, and they’re given the freedom to teach their way. In South Korea, intense competition drives students to study up to 15 hours a day, but it comes with high emotional stress. And in Poland, simple reforms, like delaying academic tracking, leveled the playing field and boosted results across the board.