The pioneers of the hedge-fund industry changed Wall Street. By placing at times brilliant bets in the market they gained considerable personal wealth, but according to New Yorker staff writer Sheelah Kolhatkar, an outsize influence on society too. She joins The Agenda to discuss the seven-year investigation into Steven A. Cohen, one of the industry's biggest success stories, and her book, "The Black Edge: Inside Information, Dirty Money, and the Quest to Bring Down the Most Wanted Man on Wall Street."