Publisher HarperCollins announced Monday that in six days, Harper Lee's second novel, Go Set a Watchman, has sold 1.1 million copies including hardcovers, e-books, and audiobooks. An eye-popping statistic, to be sure. In fact, it's the fastest-selling book HarperCollins has ever published. But it's not the fastest-selling book of 2015. That title, The Los Angeles Times reports, goes to a different reimagination of a much-loved book: E.L.