He has been on every talk show and financial news panel in the land, arguing with, among others, Bill O'Brien, the president of the Bats Global Markets stock exchange, about whether or not he and his cohorts are ripping off their customers. If the 53-year-old started off angry, opposition to the book has sharpened his stance into a moral crusade. "I find this story really upsetting," he says over lunch in LA, where his publicity tour just ended. "The idea that the smartest, richest elites of society find this an acceptable activity. This predatory activity."

If it's emotional for Lewis, then the responses have been emotional too, given how unequivocal his accusations are. The cornerstone of Flash Boys, which sold a staggering 130,000 copies in the US in its first week of publication, is a discovery made by an obscure Canadian banker, Brad Katsuyama, who noticed that whenever he tried to execute a trade, the stock price moved before the order went through.