Big banks survived the financial crisis, but their ability to attract top young talent may not. That's the argument of Kevin Roose, author of the book "Young Money," which chronicles three years in the lives of eight young, and increasingly disenchanted, investment bank employees. Roose discusses why some of the junior bankers he shadowed have left finance; what banks can -- and can't -- do to change their cultures; and how the industry's efforts to promote diversity are still falling short.