Steven A. Cohen is a Wall Street legend. Born into a middle class family in a decidedly upper class suburb on Long Island, he was unpopular in high school and unlucky with girls. Then he went off to Wharton, and in 1992 launched the hedge fund SAC Capital, which grew into a $15 billion empire. He cultivated an air of mystery and reclusiveness -- at one point, owned the copyright to almost every picture taken of him -- and also of extreme excess, building a 35,000 square foot house in Greenwich, flying to work by helicopter, and amassing one of the largest private art collections in the world. But on Wall Street, he was revered as a genius: one of the greatest traders who ever lived. That public image was shattered when SAC Capital became the target of a sprawling, seven-year criminal and SEC investigation, the largest in Wall Street history, led by an undermanned but determined group of government agents, prosecutors, and investigators. Experts in finding and using "black edge" (inside information), SAC Capital was ultimately fined nearly $2 billion -- the largest penalty in history -- and shut down. But as Sheelah Kolhatkar shows, Steven Cohen was never actually put out of business. He was allowed to keep trading his own money (in 2015, he made $350 million), and can start a new hedge fund in only a few years. Though eight SAC employees were convicted or pleaded guilty to insider trading, Cohen himself walked away a free man.