Try to count cards at a blackjack table in a casino, and you may be escorted from the premises. But use your math skills on the stock market, and you may be richly rewarded.
Case in point: Jim Simons, an extremely adept mathematician and former code-breaker who has worked the stock markets better than anyone alive. The story of his rising fortune--up to $23 Billion lately--is told by Wall Street Journal reporter Gregory Zuckerman in The Man Who Solved the Market: How Jim Simons Launched the Quant Revolution.
Simons' riches have led to unprecedented financial and even political power; we get the story in this interview with the author.