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 being made not by humans, but by mathematical models. In theory, this should lead to greater fairness: Everyone is judged according to the same rules, and bias is eliminated.

But as mathemetician and former quant Cathy O’Neil reveals in Weapons of Math Destruction, the opposite is true. The models being used today are opaque, unregulated, and uncontestable, even when they’re wrong.