The UN commitment to achieving the Millennium Development Goals (MDGs) by 2015 poses a major challenge. It is, first and foremost, a political challenge to wealthy countries, to provide the necessary transfer of resources, and to developing countries, to make effective use of these transfers. But it is also an intellectual challenge, to economists and other scientists, to better understand the processes by which the MDGs can be achieved. This article focuses on two aspects. On the substantive side, it examines how we can achieve increased funding for development, particularly via new methods of finance, such as global taxes. On the intellectual side, it describes how a new branch of economics is developing – global public finance – that can contribute to the analysis of new sources of funding for the MDGs and of the working of the global economy.