Whether we're building Lego models or actual cities, grilled-cheese sandwiches or strategic plans, our minds tend to add before taking away. Even when we do think of it, subtraction can be harder to pull off, because an array of biological, cultural, and economic forces push us toward more. But as Leidy Klotz suggests, we have a choice—by diagnosing our neglect of subtraction, we can treat it. Here Klotz introduces design geniuses, Nobel Prize-winners, rock stars, and everyday heroes, who have in some form or another subtracted to advance knowledge, heal the planet, and even tell better jokes, a process that can revolutionize our day-to-day lives.