Nominated for the National Book Award and a New York Times bestseller, this book by a former Wall Street quant sounds the alarm about the mathematical models that permeate our modern lives and threaten our social fabric. We live in the age of the algorithm. Increasingly, the decisions that affect our lives—where we go to school, whether we get a car loan, how much we pay for health insurance—are made not by people, but by mathematical models. Theoretically, this should lead to more fairness: everyone is judged by the same rules, and biases are eliminated. However, as Cathy O'Neil demonstrates in this urgent and necessary book, the opposite is true. The models used today are opaque, unregulated, and unchallengeable, even when they are wrong. Most concerning is that they reinforce discrimination: when a poor student is denied a loan because a credit model classifies him as too risky based on his zip code, he is...