Picture a stock market: If you imagine yourself ringing up a broker and asking him to find a seller for, say, 10,000 shares of Google, you’re about ten years behind. Welcome to the world of e-trading, where you and your seller can theoretically exchange stocks electronically without needing to go through that pesky broker. But high-frequency traders—the people behind the mysterious flash crash of May 6, 2010—are out to squeeze the profit out of you both, and a small handful of talented, dedicated people want to change that. Flash Boys is an intricate yet accessible history of the contemporary stock market and a handy introduction to the tactics (and profit-mongering) of high-frequency trading. But it’s also the encouraging story of the rare few who, instead of putting their talents to squeezing every last penny out of unsuspecting investors, choose to set a moral example so that one day, we may stop thinking of the terms “fairness” and “Wall Street” as polar antonyms.