Sheryl WuDunn and her husband, Nick Kristof, won a Pulitzer for their New York Times coverage of the 1989 Tiananmen Square protests. Their joint reporting work in China and other developing nations convinced them both that, just as slavery was the moral issue of the 19th century, sex trafficking, gender-based violence and other abuses make women's rights the moral issue of the 21st.

In their book Half the Sky: Turning Oppression into Opportunity for Women Worldwide, WuDunn and Kristof make the case for empowering women as a means of development. Women tend to spend more on education, nutrition and business, the economic engines of growth in a community. And if we can find ways to develop the untapped potential of the millions of women who are now left uneducated, denied basic rights, oppressed and threatened -- we'll turn on a firehose of economic power that could transform the developing world.