Facebook COO Sheryl Sandberg's new book, Lean In, is a No. 1 bestseller. And the debate over her views on women in the workplace and society's gender bias has taken over magazines, TV shows, and the Internet. But is the book all hype, or actually helpful? We read it and found that it's filled with practical advice for women trying to get ahead at work and at home. Watch now for the four best pieces of advice from the much-talked-about book.