Sheryl Sandberg's best-seller "Lean In: Women, Work, and the Will to Lead" launched a national conversation on gender in the workplace and an online community of millions of working women ready to bulldoze the barriers they face. Four years later, Sandberg says working women are no better off. They are facing pushback in business and in politics, both in the U.S. and around the world. Read more on USAToday.com.