In 2000, 189 countries collectively adopted the United Nations Millennium Declaration, which evolved into a set of concrete targets called the Millennium Development Goals (MDGs). These ambitious targets – ranging from halving extreme poverty and reducing maternal mortality by three-quarters to achieving universal primary schooling and halting (and beginning to reverse) the spread of HIV/AIDS – are supposed to be met by the end of 2015. As the deadline approaches, development experts are debating a new question: What comes next?