Do you ever wonder why so many movies now have a number at the end? Anita Elberse, professor at Harvard Business School, certainly did. In her new book, Blockbusters: Hit-making, Risk-taking, and the Big Business of Entertainment, Elberse argues that, despite living in a world with more media sources and entertainment options than ever, our tastes are converging on the flashiest blockbuster hits and the biggest superstars.