Why do the keypads on drive-up cash machines have Braille dots? Why are round-trip fares from Orlando to Kansas City higher than those from Kansas City to Orlando? For decades, Robert Frank has been asking his economics students to pose and answer questions like these as a way of learning how economic principles operate in the real world-which they do everywhere, all the time. Once you learn to think like an economist, all kinds of puzzling observations start to make sense. Drive-up ATM keypads have Braille dots because it's cheaper to make the same machine for both drive-up and walk-up...