Three women were awarded the 2011 Nobel Peace Prize on Friday, becoming the first women to win since 2004. Liberian President Ellen Johnson Sirleaf, Leymah Gbowee, also of Liberia, and Tawakul Karman of Yemen will share the award. The Norwegian Nobel committee honored the three women for "their non-violent struggle for the safety of women and for women's rights to full participation in peace-building work." Johnson Sirleaf is the first democratically-elected female head of state in Africa, Gbowee is an activist, and Karman is a leading figure in Yemen's pro-democracy movement. One of the many people around the globe who was delighted by the announcement was Sheryl WuDunn. She and her husband, New York Times columnist Nicholas Kristof, wrote the book "Half the Sky: Turning Oppression into Opportunity for Women Worldwide," which advocates improving the conditions of women in order to improve the world.