How does a state's natural resource wealth influence its economic development? For the past fifty years, versions of this question have been explored by both economists and political scientists. New research suggests that resource wealth tends to harm economic growth, yet there is little agreement on why this occurs. This article reviews a wide range of recent attempts in both economics and political science to explain the "resource curse." It suggests that much has been learned about the economic problems of resource exporters but less is known about their political problems. The disparity between strong findings on economic matters and weak findings on political ones partly reflects the failure of political scientists to carefully test their own theories.